Here's a detailed guide to Subterror! One of the new decks to receive support from the Scarred Resonance main box.

Subterror gameplay guide
Overview

Subterror is a deck that has been a part of Duel Links history for a long time.
First appearing from the Blazing Rose main box, Subterror had a boom period thanks to its initial support that lasted from May to September 2019. However, since then, the deck has largely "slept" and is no longer a prominent presence in the meta.
Until recently! After five and a half years of silence , Subterror has been resurrected thanks to new support cards introduced in the Scarred Resonance Main Box, along with a brand new Skill . These additions have given Subterror important tools to enhance the control playstyle that is the deck’s identity, and help it keep up with the pace of the modern Duel Links meta .
The cards belong to the Archetype - Little Friends
Subterror is a deck of Earth-type monsters that consists of two main parts:
Subterror low-level monster group: These are the cards that start combos, extend turns, and disrupt the opponent's gameplay.
The high-level monster group called "Behemoth" : These are Boss monsters with high stats, specialized in eliminating monsters, creating pressure on the field, interrupting turns and acting as the "finishing blows" of the deck.
Most Subterror monsters have effects that activate when flipped face up , or can flip their own or your opponent's cards face up/down to launch combos or cause disruption. In the first part of this guide, we'll look at the lower level monsters first, then move on to the Behemoths.
Subterror Guru (x3)








Subterror Guru
ATK:
1600
DEF:
1800
FLIP: You can add 1 "Subterror" card from your Deck to your hand, except "Subterror Guru". You can target 1 other face-up monster on the field; change that monster, also this card, to face-down Defense Position. This is a Quick Effect if you control another "Subterror" card. You can only use each effect of "Subterror Guru" once per turn.
This is one of the two most important monsters in the deck, possessing two key effects and playing a core role in three aspects:
Searching for cards : Guru works extremely well with the Field Spell - The Hidden City . When you set Guru face down, you can use Hidden City to immediately reveal Guru, and find any Subterror card from your deck. The most common are Subterror Fiendess or Subterror Final Battle – important cards that will be discussed later.
Disruption by Flipping : Guru can flip himself face down at the same time as an opponent's monster. This is a great way to bait or disable negate monsters like Void Ogre Dragon or Crystal Wing Synchro Dragon . What's special is that if you have another face-up Subterror on the field, this effect becomes a quick-effect, allowing you to do this during your opponent's turn, thereby breaking combos like Bone Archfiend or blocking plays from the Extra Deck.
Nemesis of the Underground Terror Activation : Guru is one of two cards that can activate this ability, by revealing a Level 4 Subterror. You can set The Hidden City or Subterror Final Battle from your hand or deck, with Final Battle being activated that turn if set with an ability. If you set from your hand, you also draw 1 card. And if only your opponent has a monster, you can call a Level 5 or higher Subterror from your hand or deck in face-down defense position, which can be flipped face-up that turn.
Subterror Fiendess (x3)








Subterror Fiendess
ATK:
800
DEF:
500
When your opponent activates a card or effect (Quick Effect): You can send this card from your hand or field to the GY, then target 1 "Subterror" monster you control; negate the activation, then change the targeted monster to face-down Defense Position. You can target 1 face-up monster you control; change it to face-down Defense Position, and if you do, Special Summon 1 "Subterror" monster from your hand or GY, in face-up or face-down Defense Position. You can only use each effect of "Subterror Fiendess" once per turn.
The deck's remaining key monster, with two extremely powerful effects:
Effect 1 : When your opponent activates a card or effect, you can send Fiendess from your hand or field to the Graveyard, then target 1 Subterror monster you control to negate your opponent's effect and turn that monster face-down. Important : the negate effect will occur even if that Subterror monster is discarded or has been turned face-down by another effect – meaning the negate does NOT depends on flipping , but rather the other way around. It’s the archetype’s most powerful disruption tool, and it ’s easy to find thanks to Guru and Hidden City. Flipping also “resets” monsters, allowing you to re-use the flip effect during your opponent’s turn – very effective when combined with Guru or Behemoths.
Effect 2 : Allows you to flip a monster you control face-down to special summon a Subterror from your hand or Graveyard, either face-up or face-down in Defense Position. This expands the field, summons additional monsters to make an Extra Deck like Knightmare Phoenix or Knightmare Unicorn , and creates a powerful long-term game by reviving Guru or Behemoth from the Graveyard.
Interactions with Behemoths : All Behemoths have the effect: "When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can call this card from your hand in defense position." This is a "when... you can" trigger, meaning flipping it face-down must be the last action in the chain.
Fiendess's effect 1 will summon Behemoth if it is Chain Link 2 or lower, and the negate is chain link 2 and the negated action is chain link 1, so nothing happens after Fiendess.
The 2-flip effect and special summon happen at the same time, so flipping is still the final action and Behemoth can be summoned in the new chain.
This also applies to Guru if it's Chain Link 1 – when Guru flips himself and an opponent's monster face down at the same time, you can still summon Behemoth afterwards.
Subterror Nemesis Warrior (x0-1)








Subterror Nemesis Warrior
ATK:
1800
DEF:
1200
During either player's turn: You can send 1 "Subterror" monster from your Deck to the Graveyard; Tribute this card and at least 1 other monster so the total original Levels Tributed equal or exceed the Level of that "Subterror" monster in the Graveyard, and if you do, Special Summon that monster in face-up or face-down Defense Position. If a "Subterror Behemoth" monster is flipped face-up while this card is in your Graveyard: You can Special Summon this card. You can only use each effect of "Subterror Nemesis Warrior" once per turn.
Once a x3 staple in the deck, Subterror Nemesis Warrior is now a secondary support card, largely because it's the only level 4 monster other than Guru that can trigger its ability. However, the card is now too slow to use more than one copy, and its effects aren't as valuable as they once were.
Effect 1 : Send a Subterror from your deck to the Graveyard, then Tribute the Warrior and another monster with a total level equal to or higher to summon that monster in defense position (face-up or face-down). The monster being sacrificed does not need to be a Subterror, which opens up some special combos (for example with Anchamoufrite ). However, since the summoning is not a cost, it is easily negated by Effect Veiler, Ghost Mourner , or DD Crow , causing the combo to fall apart.
Effect 2 : When the Warrior is in the Graveyard, and a face-down Behemoth is flipped face-up, the Warrior can be special called from the Graveyard. However, this effect is no longer worth it because it is difficult to send the Warrior to the Graveyard unless using its main effect or discarding with Stalagmo . Additionally, only Behemoths can trigger this effect, not low-level Subterrors. Additionally, most modern decks only run 1-2 Behemoths, making this loop too slow and not worth the investment.
Subterror Nemesis Archer (x0-1)








Subterror Nemesis Archer
ATK:
1600
DEF:
1400
At the start of the Damage Step, if this card attacks an opponent's face-down Defense Position monster, and you control another "Subterror" monster: You can shuffle that opponent's monster into the Deck. If this card on the field is destroyed by battle or card effect and sent to the GY: You can Special Summon 1 "Subterror" monster from your Deck in face-up or face-down Defense Position. You can only use each effect of "Subterror Nemesis Archer" once per turn.
A new card from Scarred Resonance .
Effect 1 : When attacking a face-down enemy monster, if you control another Subterror, push that monster back to the deck immediately upon entering the Damage Step. Combines nicely with Guru or Ultramafus , turning Archer into a form of non-targeted, non-destructive removal.
Effect 2 : If destroyed by battle or effect, you can summon a Subterror from your deck in face-down defense position. This is a good float, and can be exploited in a meta that uses a lot of Dogmatika Punishment – you can send Elder Entity N'tss to destroy your opponent's deck and then blow up Archer to summon another Subterror.
However, Archer is quite meta-dependent. Space is a big issue since you usually already have Guru + Behemoth + Fiendess, making it difficult to find room for Archer. Also, summoning him is difficult since the priority of other combos is usually higher.
Subterror Nemesis Defender (x0)








Subterror Nemesis Defender
ATK:
100
DEF:
2000
During either player's turn, when your opponent activates a card or effect that targets exactly 1 Set monster you control (and no other cards), or when a Set monster you control is targeted for an attack by an opponent's monster: You can send this card from your hand or face-up from your field to the Graveyard, then target another monster you control that would be an appropriate target; that card/effect/attack now targets the new target. While you control a Set monster, this card cannot be destroyed by battle or card effects.
No need for a long analysis – this card is completely outmeta due to the existence of Fiendess.
Effect 1 : Send Defender from your hand or field to change the attack target or effect of a face-down monster you control to another face-down monster. But the setup for this combo is time-consuming and impractical.
Effect 2 : If you control any face-down card (including backrow), Defender cannot be destroyed by battle or effects. However, modern Extra Deck tools like Knightmare Unicorn easily bypass this.
Summary: Don't play Defender, Fiendess does a good job of protecting.
Cards of Archetype - Behemoth Bosses
All Behemoths have 2 common effects:
When a face-up monster you control is face-down and you have no other face-up monsters, you can special summon Behemoth from your hand in defense position.
Once per turn, you can flip Behemoth face down.
These effects make it easy to expand the board through Fiendess and Guru , and take advantage of flip control to create complex disruption chains. Calling Behemoth at the right time can help trigger Guru 's Quick Effect , or link with cards like Final Battle to gain advantage.
Subterror Behemoth Umastryx (x1)








Subterror Behemoth Umastryx
ATK:
2000
DEF:
2700
FLIP: You can target 1 monster your opponent controls; banish it. You can only use this effect of "Subterror Behemoth Umastryx" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.
This is the main boss of the Subterror deck. When flipped face up, you can choose 1 opponent monster and banish it. This is an extremely powerful removal method because it does not specify destruction or sending it to the Graveyard – helping to bypass common defensive effects.
Despite its simple mechanics, Umastryx's value lies in when you use it. Keeping it face up to keep Guru alive, flipping it face down with its own effect or with Fiendess , and then triggering Final Battle to flip it back up are all interactions that require situational reading, meta analysis, and understanding of your opponents.
Subterror Behemoth Ultramafus (x0-1)








Subterror Behemoth Ultramafus
ATK:
3000
DEF:
1800
FLIP: You can change all other face-up monsters on the field to face-down Defense Position. You can only use this effect of "Subterror Behemoth Ultramafus" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.
This is the biggest monster of the archetype. When flipped face-up, it flips all monsters on the field face-down.
This effect is extremely important when going later, especially in a matchup with decks like Lyrilusc or decks that protect against targets. In addition, it also helps reset all of your Subterror to prepare for the next turn. Interacts well with Subterror Cave Clash to buff ATK.
The rest.... (x0)








Subterror Behemoth Stalagmo
ATK:
2800
DEF:
2100
FLIP: You can discard 1 "Subterror" monster, and if you do, draw 2 cards. You can only use this effect of "Subterror Behemoth Stalagmo" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.







Subterror Behemoth Fiendess
ATK:
2000
LINK-2
Link Arrow:
Bottom-Left
Bottom-Right
2 Flip monsters Gains ATK equal to the combined original Levels of the "Subterror" monsters used for its Link Summon x 100. During your Main Phase: You can send 1 Flip monster from your Deck to the GY, and if you do, Special Summon 1 monster from your hand in face-down Defense Position to your zone this card points to. You can only use this effect of "Subterror Behemoth Fiendess" once per turn. Once per turn, if a monster this card points to is flipped face-up: Add 1 Flip monster from your Deck or GY to your hand.








Subterror Behemoth Speleogeist
ATK:
3000
DEF:
1400
FLIP: You can target 1 monster on the field; change it to face-up Attack Position if it is in Defense Position, also change its ATK to 0. You can only use this effect of "Subterror Behemoth Speleogeist" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.








Subterror Behemoth Phospheroglacier
ATK:
2600
DEF:
2500
FLIP: You can send 1 card from your Deck to the Graveyard. You can only use this effect of "Subterror Behemoth Phospheroglacier" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.








Subterror Behemoth Dragossuary
ATK:
2400
DEF:
1600
FLIP: You can activate this effect; this turn, "Subterror" cards you control cannot be destroyed by your opponent's card effects. You can only use this effect of "Subterror Behemoth Dragossuary" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.








Subterror Behemoth Stygokraken
ATK:
1400
DEF:
2600
FLIP: You can target Set cards on the field, equal to the number of "Subterror Behemoth" monsters you control; destroy them. You can only use this effect of "Subterror Behemoth Stygokraken" once per turn. When a face-up monster you control is flipped face-down, if you control no face-up monsters: You can Special Summon this card from your hand in Defense Position. Once per turn: You can change this card to face-down Defense Position.
Remaining Behemoths (not recommended)
Stygokraken : Used to be a non-target removal with backrow, but required the number of face-up Behemoths on the field to match the number of cards the opponent set – too slow and easy to block.
Stalagmo : Has the effect of discarding 1 Subterror to draw 2 cards – quite powerful when combined with Nemesis Warrior. However, the setup to call it is too resource-intensive, and most of the time the only Subterror you want to discard is Warrior.
Speleogeist : Have to set the opponent's monster then flip it and attack yourself - too roundabout, the effect is not effective compared to current tools.
Phospheroglacier : Can send any card to the Graveyard – a very versatile effect, works with Kiteroid, Shaddoll, Farfa, etc. However, is limited by the skill (only summons Subterror), so not optimal.
Dragossuary : Provides protection from being destroyed by effects – but only works when the monster is face up, not suitable for flip control playstyle.
Subterror Behemoth Fiendess (Link): The archetype's Link Monster but almost no one uses it. Strict summoning requirements (must use Guru and Behemoth), weak stats, and anti-synergy with the rest of the deck. Some decks even remove it completely to play a more compact, efficient Extra Deck.
Spell/ Trap thuộc Archetype
This is an essential part of understanding the power and stability of the Subterror deck. Although the number of key spells and traps is small (thankfully, this archetype does not rely heavily on the backrow), each card has a huge impact.
The Hidden City (x2-3)








The Hidden City
When this card is activated: You can add 1 "Subterror" monster from your Deck to your hand. Once per turn: You can change 1 face-down Defense Position "Subterror" monster you control to face-up Attack or Defense Position. Once per turn, when an opponent's monster declares an attack: You can change 1 face-down Defense Position "Subterror" monster you control to face-up Attack or Defense Position, then you can negate the attack. You can only activate 1 "The Hidden City" per turn.
As a 3-limit Field Spell, this card also acts as a combo starter and has three effects, all of which are very important:
When activated, you can add 1 Subterror monster from your deck to your hand (insert joke about Field Spell archetypes having search).
Once per turn, you can select 1 face-down Subterror monster on your side of the field and flip it into attack or defense position.
Once per turn, when your opponent declares an attack, you can flip 1 face-down Subterror you control, then negate that attack.
Effect 1 is pretty self-explanatory: find Guru if you don't have one, start combo; if you already have Guru, find Fiendess; if you have both, get Umastryx.
Effect 2 is what makes Guru a combo starter, allowing you to flip Guru on the turn it’s set to find a card. Find Fiendess if you don’t have one, or find Subterror Final Battle . Note: this is soft once per turn – meaning if you play a Hidden City to flip a monster, then play another Hidden City (on the following turn), you can still flip another monster. This is useful when you’re locked in battle position, like when you’re under the effect of Gravity Axe - Grarl .
Effect 3 allows you to flip Subterror in the Battle Phase, giving your opponent a chance to interrupt their turn, although it depends on whether they attack or not – if they understand the card, they'll likely dodge. Still, it helps you survive matchups where the Battle Phase is important, like Predaplant, which can be difficult to overcome without a Predator Counter.
Note: This card does not count as 'Subterror', so it cannot be found with Guru. You can only find it with Terraforming , which is limited to 1.
Hidden City Popularity:
2 Hidden City + 1 Terraforming: keep the Limit 3 slot for other cards like Ice Dragon's Prison or Lost Wind .
3 Hidden City, no Terraforming: if you want to keep Limit 1 for cards like Super Polymerization .
3 Hidden City + 1 Terraforming: maximize stability – 6 starters in a 20-card deck = ~78% combo opening. A good number, but still not reassuring for some people.
Subterror Final Battle (x2-3)








Subterror Final Battle
Activate 1 of these effects, also, after that, Set this card face-down instead of sending it to the GY. ● Change 1 Set "Subterror" monster on the field to face-up Attack or Defense Position. ● Change 1 face-up "Subterror" monster on the field to face-down Defense Position. ● ATK/DEF of 1 "Subterror" monster on the field become equal to its combined original ATK/DEF until the end of this turn. ● This turn, activated effects of "Subterror" cards cannot be negated.
The archetype's most famous (and infamous) trap. It can be activated on the turn it's set by ability, and it doesn't go to the Graveyard after use, instead it's flipped face-up for later use. Each effect is useful and isn't limited to one turn, meaning you can use multiple copies in the same turn, and repeat each effect multiple times.
Effects:
Flip 1 Subterror face up (attack or defense position).
Flip 1 Subterror face up to face down defense.
ATK/DEF of a Subterror = sum of its original ATK + DEF.
During this turn, Subterror effects cannot be negated.
Effect 1 is the one you'll use most often to flip Guru/Umastryx/Ultramafus on your opponent's turn, interrupting their combo.
Effect 2 is also very important: it allows you to reset Subterror, to flip it again later. It can also be used at the start of the Battle Phase to take advantage of Hidden City's effect 3. In mirror matches, you can use it to flip your opponent's Subterror, but be careful because it will reset their flip effect - only use it if you have a way to prevent them from flipping it back or negate the flip effect.
Effect 3 is an OTK tool – Umastryx will go from 2000 to 4700 ATK, Guru from 1600 to 3400. Since it changes stats, you can use it in the Damage Step, which helps overcome some of the disruptions.
Effect 4 used to be a “useless” effect in the pre-handtrap era, but is now extremely important. Used to protect combos from Effect Veiler – it cannot block negate activation like Crystal Wing , but can block negate resolution like Veiler , ensuring you can still find cards, negate, or flip monsters in time.
Two advanced interactions:
When you flip Final Battle, it counts as a face-up Subterror card on the field, allowing Guru to use quick effects – especially important when Guru is the only one on the field.
However, if you use Final Battle to flip Subterror face-down, you will NOT be able to summon Behemoth from your hand – because the final action of the chain is Final Battle flipping itself face-down, not flipping the monster face-down.
Subterror Cave Clash (x0-1)








Subterror Cave Clash
All "Subterror" monsters you control gain 500 ATK and DEF for each Set monster on the field. Once per turn, when a "Subterror" monster you control inflicts battle damage to your opponent: You can target 1 "Subterror" card in your Graveyard, except "Subterror Cave Clash"; add it to your hand.
This card has been gaining popularity lately, not necessarily because of its effect (which isn't bad), but mainly because it's a continuous card that helps keep Guru 's fast effect going. This allows you to keep Guru under constant pressure without having to rely on summoning Behemoths on your opponent's turn, or flipping Subterror Final Battle.
About the effect:
Stat Boost: When a Subterror deals damage to an opponent, you can add 500 ATK and DEF to all Subterror monsters you control. This buff is quite effective when used with Ultramafus, but note that you will lose 500 ATK when attacking an opponent's monster since they are face-up at the beginning of the Damage Step.
Fiendess Recall: When your Subterror deals damage and survives battle, you can add 1 Subterror monster from your Graveyard to your hand. Sounds good, but it rarely happens – usually only when your opponent miscalculates or you're completely outnumbered.
Subterror Succession (x0)








Subterror Succession
Activate 1 of these effects, also, after that, Set this card face-down instead of sending it to the GY. ● Send 1 monster from your hand or face-up field to the GY, and if you do, add 1 Flip monster from your Deck to your hand with the same Attribute, but a different name, as that monster before it was sent to the GY. ● Send 1 Flip monster from your hand or face-up field to the GY, and if you do, add 1 monster from your Deck to your hand with the same Attribute but a lower original Level, as that monster before it was sent to the GY. You can only activate 1 "Subterror Succession" per turn.
Unfortunately, despite its search potential, this is still a very slow trap in the current meta. Effect 1: When you summon Subterror, you can add 1 Behemoth or Guru from your deck to your hand. Effect 2 : When a Subterror monster is sent from the field to the Graveyard, you can search 1 Fiendess from your deck .
The problem is: we only use 1–2 Behemoths, Guru can be recharged by Fiendess, and Fiendess is easily found by Guru. So the effect is duplicated and much slower than Final Battle, which is a more desirable trap.
Subterror Behemoth Burrowing (x0)








Subterror Behemoth Burrowing
You can banish 1 "Subterror" monster from your Graveyard; for the rest of this turn, face-down monsters you control cannot be destroyed by card effects, and your opponent cannot target them with card effects. If this card on the field is destroyed by a card effect: You can add 1 "Subterror" monster from your Deck to your hand. You can banish this card from your Graveyard, then target 1 "Subterror" monster you control; change it to face-down Defense Position.
When you set or summon a card face-down, you can banish this card from the Graveyard to protect your set card from being destroyed by effects that turn. But this is a slower, weaker version of Lord of the Heavenly Prison : it cannot be activated from the hand, does not summon a body, does not allow searching for cards, and requires banishing lost resources.
Tech Cards
That's it for the Archetype section, there's a lot more to consider, but now it's time to move on to the next part of the deck — The Outer Cards That Are Not Archetypes.
Super Polymerization (x0-1)
Basically, Subterror rarely uses the Extra Deck and relies heavily on monsters in the Main Deck. This means you have up to 9 empty Extra Deck slots to flexibly adjust to the current meta.
Encountering a lot of DARK monsters? Starving Venom Fusion Dragon is the perfect choice!
Encountering a Dragonmaid? Get your House Dragonmaid ready to deal with it!
Pot of Duality (x2-3)
A stability tool, often used in 2 or 3 copies to ensure you get what you lack in the opening. While it counteracts Fiendess's 2nd effect (since it can't be special summoned after use), a field ahead of Subterror's effectiveness doesn't depend on opening the strongest combo (Fiendess + Guru + Umastryx). Additionally, you can still use it when going later because special summoning from the ability isn't affected by Pot of Duality .
Nibiru the Primal Being (x0-2)








Nibiru, the Primal Being
ATK:
3000
DEF:
600
During the Main Phase, if your opponent Normal or Special Summoned 5 or more monsters this turn (Quick Effect): You can Tribute as many face-up monsters on the field as possible, and if you do, Special Summon this card from your hand, then Special Summon 1 "Primal Being Token" (Rock/LIGHT/Level 11/ATK ?/DEF ?) to your opponent's field. (This Token's ATK/DEF become the combined original ATK/DEF of the Tributed monsters.) You can only use this effect of "Nibiru, the Primal Being" once per turn.
An incredibly powerful tech when going later. Subterror only blocks you from summoning non-Subterror monsters from your Main Deck during your turn, not your opponent's. Subterror is flexible enough to run handtraps when the meta suits it, and at the time of writing, Nibiru is a huge hitter in top meta decks. Thanks to its ability to flip itself, Subterror is hard to hit by Nibiru, while you can clear your opponent's field and leave a harmless token. Unfortunately, this card is on the paywall, so only those who are lucky or don't mind investing can use it.
Lord of the Heavenly Prison (x0-2)








Lord of the Heavenly Prison
ATK:
3000
DEF:
3000
During your Main Phase: You can activate this effect; this card in your hand becomes revealed until the end of your opponent's turn. While this card is revealed by this effect, Set cards on the field cannot be destroyed by card effects. If a Set Spell/Trap Card is activated (except during the Damage Step): You can Special Summon this card from your hand, then, if you activated this effect while this card was revealed, you can reveal and Set 1 Spell/Trap directly from your Deck, but banish it during the End Phase of the next turn. You can only use 1 "Lord of the Heavenly Prison" effect per turn, and only once that turn.
This card's protective effect goes beyond Subterror Behemoth Burrowing thanks to its ability to activate at the start of your Main Phase, before you commit any cards to the field. It protects both your backrow and your face-down monsters from being destroyed. Additionally, like with Nibiru, Nemesis of the Underground Terror doesn't block you from playing Lord during your opponent's turn, making this a very useful extra body.
When Lord is summoned, you can find 1 Spell/Trap from your deck and set it on the field, then banish it at the end of the turn. This is very useful for getting rid of a brick hand (e.g. finding Terraforming) or opening up a path to destroy the field (e.g. finding Super Poly). Finally, it is important to note that Final Battle 's 4th effect does not require you to have a Subterror monster on the field, so you can activate Final Battle, use 4th effect, and then summon Lord easily.
Terrors of the Overroot (x0-2)
A tech pick against a meta that's heavy on anti-destruction. This card can remove a valuable card from your opponent's field, then replace it with a lesser one from their Graveyard. Can be used on monsters, spells, or traps, making it very versatile – especially effective against field spells or continuous spell/traps. Be careful with the cards you return to them, though, as you may set them up for a counterattack.
Dogmatika Punishment (x0-2)








Dogmatika Punishment
Target 1 face-up monster your opponent controls; send 1 monster with an equal or higher ATK from your Extra Deck to the GY, and if you do, destroy that monster. Until the end of your next turn after this card resolves, you cannot Special Summon monsters from the Extra Deck. You can only activate 1 "Dogmatika Punishment" per turn.
Effective in metas with little protection from destruction. This card lets you destroy 1 monster, and if you send Elder Entity N'tss , you can destroy another one on the field. Being locked to the Extra Deck doesn't affect Subterror much. However, opponents can avoid this effect by preventing destruction, flipping their own monsters face down, or using avoidance effects like Salamangreat Burning Shell.
Sol and Luna (x0-2)








Sol and Luna
Target 1 monster you control and 1 monster your opponent controls; apply the following effect on each monster, depending on its battle position. ● Face-up: Change it to face-down Defense Position. ● Face-down: Change it to face-up Defense Position. You can only activate 1 "Sol and Luna" per turn.
A selection box card, but extremely powerful with Subterror. Allows you to flip 1 of your own monsters face up and 1 of your opponent's monsters face down at the same time, allowing you to take advantage of Final Battle or Hidden City to flip Subterror, while also causing flexible disruption. In Subterror, sometimes more effective than Book of Moon.
Titanocider (x0-2)








Titanocider
Target 1 face-up monster your opponent controls that was Special Summoned from the Extra Deck; change its ATK to 0, and if you do, negate its effects. If your opponent Special Summons a monster(s) from the Extra Deck while this card is in your GY, except the turn this card was sent to the GY: You can Set this card. You can only use each effect of "Titanocider" once per turn.
The last Selection Box pick on this list. It is a retriggerable trap that disables monsters from the Extra Deck and reduces their ATK to 0 – effective even in the Damage Step, and can help you OTK with a 4700 ATK Umastryx. It has a similar role to Lost Wind , but does not take up the Limit 3 slot.
Ice Dragon's Prison (x0-1)
Only play when you only have 2 Hidden Cities. IDP is a powerful trap that can remove 1 resource from your opponent's Graveyard, then use it to remove 1 monster of the same type from your opponent's field. It's a very effective way to remove 2 monsters with 1 trap.
Lost Wind (x0-1)








Lost Wind
Target 1 face-up Special Summoned monster on the field; negate its effects, also its original ATK is halved. If a monster is Special Summoned from your opponent's Extra Deck, while this card is in your GY (except during the Damage Step): You can Set this card, but banish it when it leaves the field.
Like IDP, you only use it if you don't (or can't) use 3 Hidden Cities. Same role as Titanocider, but can be reactivated once. Affects all special summoned monsters, not just those from the Extra Deck. Even though it only halves ATK, it's usually enough to get past that monster - though not enough to OTK it.
Extra Deck
This is arguably the least important part of the deck, so there's not much to say. These are mostly tech options that you'll rarely need, or just serve as bait for Dogmatika Punishment if you do play that card.
Knightmare Unicorn, Knightmare Cerberus and Knightmare Phoenix (.)







Knightmare Unicorn
ATK:
2200
LINK-3
Link Arrow:
Left
Right
Bottom
2+ monsters with different names If this card is Link Summoned: You can discard 1 card, then target 1 card on the field; shuffle it into the Deck, then, if this card was co-linked when this effect was activated, you can draw 1 card. You can only use this effect of "Knightmare Unicorn" once per turn. While any co-linked "Knightmare" monsters are on the field, for your normal draw in your Draw Phase, draw 1 card for each different card name among those co-linked "Knightmare" monsters, instead of drawing just 1 card.







Knightmare Cerberus
ATK:
1600
LINK-2
Link Arrow:
Top
Left
2 monsters with different names If this card is Link Summoned: You can discard 1 card, then target 1 Special Summoned monster in your opponent's Main Monster Zone; destroy it, then, if this card was co-linked when this effect was activated, you can draw 1 card. You can only use this effect of "Knightmare Cerberus" once per turn. Co-linked monsters you control cannot be destroyed by card effects.







Knightmare Phoenix
ATK:
1900
LINK-2
Link Arrow:
Top
Right
2 monsters with different names If this card is Link Summoned: You can discard 1 card, then target 1 Spell/Trap your opponent controls; destroy it, then, if this card was co-linked when this effect was activated, you can draw 1 card. You can only use this effect of "Knightmare Phoenix" once per turn. Co-linked monsters you control cannot be destroyed by battle.
The Extra Deck staple trio helps you eliminate specific threats:
Knightmare Phoenix : bait dangerous backrows.
Knightmare Cerberus : especially useful for handling Nibiru tokens .
Knightmare Unicorn : Removes without destroying any cards on the field.
Elder Entity N'tss (x0-2)








Elder Entity N'tss
ATK:
2500
DEF:
1200
1 Synchro Monster + 1 Xyz Monster Must be Special Summoned (from your Extra Deck) by sending the above cards you control to the GY. (You do not use "Polymerization".) Once per turn: You can Special Summon 1 Level 4 monster from your hand. If this card is sent to the GY: You can target 1 card on the field; destroy it. You can only Special Summon "Elder Entity N'tss(s)" once per turn.
Only use if you play Dogmatika Punishment. This is the best target to send, because when sent to the Graveyard, you can destroy any card on the field. Can be used in conjunction with Archer to call Guru in a desperate situation, or used with Umastryx if you need to quickly remove a threat.
Leaves that come with Super Poly








Diplexer Chimera
ATK:
2000
DEF:
800
2 Cyberse monsters Once per turn: You can Tribute 1 Cyberse monster; Spell/Trap Cards, and their effects, cannot be activated during the Battle Phase of this turn. If this Fusion Summoned card is sent to your GY: You can target 1 "Cynet Fusion" and 1 Cyberse monster in your GY, except this card; add them to your hand. You can only use this effect of "Diplexer Chimera" once per turn.








Elemental HERO The Shining
ATK:
2600
DEF:
2100
1 "Elemental HERO" monster + 1 LIGHT monster Must be Fusion Summoned and cannot be Special Summoned by other ways. This card gains 300 ATK for each of your banished "Elemental HERO" monsters. When this card is sent from the field to the Graveyard: You can target up to 2 of your banished "Elemental HERO" monsters; add those targets to your hand.








Lyrilusc - Independent Nightingale
ATK:
1000
DEF:
0
"Lyrilusc - Assembled Nightingale" + 1 "Lyrilusc" monster If this card is Fusion Summoned using an Xyz Monster on the field as Fusion Material whose original name includes "Lyrilusc": You can increase this card's Level by the number of Xyz Materials that monster(s) had. This card gains ATK equal to its Level x 500. Unaffected by other cards' effects. Once per turn: You can inflict damage to your opponent equal to this card's Level x 500.








Fossil Warrior Skull Knight
ATK:
2400
DEF:
1100
1 Rock monster + 1 Level 5 or 6 monster Must first be Special Summoned with "Fossil Fusion". If this card attacks a Defense Position monster, inflict piercing battle damage. When this attacking card destroys a monster by battle: You can activate this effect; this card can make a second attack in a row. You can banish this card from your GY, then target 1 monster on the field; destroy it. You can only use this effect of "Fossil Warrior Skull Knight" once per turn.








The First Darklord
ATK:
4000
DEF:
4000
3 DARK Fairy monsters Your opponent cannot target Fairy monsters you control with card effects. You can only use 1 of the following effects of "The First Darklord" per turn, and only once that turn. ● If this card is Fusion Summoned using "Darklord Morningstar" as material: You can destroy all cards your opponent controls. ● During the Main Phase (Quick Effect): You can pay 1000 LP; Special Summon 1 Fairy monster from your hand or GY in Defense Position.








Fossil Machine Skull Wagon
ATK:
1700
DEF:
1500
1 Rock monster in your GY + 1 Level 5 or 6 monster Must first be Special Summoned with "Fossil Fusion". This card can make up to 2 attacks on monsters during each Battle Phase. When this card destroys an opponent's monster by battle: You can inflict 800 damage to your opponent. You can banish this card from your GY, then target 1 Spell/Trap on the field; destroy it. You can only use this effect of "Fossil Machine Skull Wagon" once per turn.








House Dragonmaid
ATK:
3000
DEF:
2000
1 "Dragonmaid" monster + 1 Dragon monster Once per turn, during the Standby Phase: You can target 1 other "Dragonmaid" monster you control; Special Summon 1 "Dragonmaid" monster from your hand or GY in Defense Position, whose Level is 1 higher or 1 lower than it. When another face-up Dragon monster(s) you control returns to your hand (except during the Damage Step): You can target 1 monster your opponent controls; destroy it.








Starving Venom Fusion Dragon
ATK:
2800
DEF:
2000
2 DARK monsters on the field, except Tokens If this card is Fusion Summoned: You can make this card gain ATK equal to 1 opponent's Special Summoned monster, until the end of this turn. Once per turn: You can target 1 Level 5 or higher monster your opponent controls; until the End Phase, this card's name becomes that monster's original name, and replace this effect with that monster's original effects. If this Fusion Summoned card is destroyed: You can destroy all your opponent's Special Summoned monsters.








Mudragon of the Swamp
ATK:
1900
DEF:
1600
2 monsters with the same Attribute but different Types Your opponent cannot target this card, or monsters on the field with the same Attribute as this card, with card effects. Once per turn (Quick Effect): You can declare 1 Attribute; this card becomes that Attribute until the end of this turn.
This is a collection of Fusion monsters that fit the current meta, used with Super Polymerization to remove 2 or more threats from the opponent's field at once. The deck doesn't necessarily rely on this Extra Deck, but when used at the right time, it can turn the tide quickly .
The matches
This section will cover the most popular and influential match-ups in the current meta.
Resonator








Red Rising Dragon
ATK:
2100
DEF:
1600
1 Fiend Tuner + 1+ non-Tuner monsters When this card is Synchro Summoned: You can target 1 "Resonator" monster in your GY; Special Summon it. You cannot Special Summon monsters from the Extra Deck the turn you activate this effect, except DARK Dragon Synchro Monsters. During your Main Phase, except the turn this card was sent to the GY: You can banish this card from your GY, then target 2 Level 1 "Resonator" monsters in your GY; Special Summon both.








Scarlight Red Dragon Archfiend
ATK:
3000
DEF:
2500
1 Tuner + 1+ non-Tuner monsters This card's name becomes "Red Dragon Archfiend" while it is on the field or in the GY. Once per turn: You can destroy as many Special Summoned Effect Monsters on the field as possible with ATK less than or equal to this card's (other than this card), then inflict 500 damage to your opponent for each monster destroyed.








Red Nova Dragon
ATK:
3500
DEF:
3000
2 Tuners + "Red Dragon Archfiend" This card gains 500 ATK for each Tuner monster in your Graveyard. Cannot be destroyed by an opponent's card effects. When an opponent's monster declares an attack: You can target the attacking monster; banish this card, and if you do, negate that attack. During the next End Phase: Special Summon this card banished by this effect.








Red Resonator
ATK:
600
DEF:
200
When this card is Normal Summoned: You can Special Summon 1 Level 4 or lower monster from your hand. When this card is Special Summoned: You can target 1 face-up monster on the field; gain LP equal to its ATK. You can only use this effect of "Red Resonator" once per turn.








Crimson Resonator
ATK:
800
DEF:
300
If you control no monsters: You can Special Summon this card from your hand. If the only other monster you control is exactly 1 DARK Dragon Synchro Monster: You can Special Summon up to 2 "Resonator" monsters from your hand or Deck, except "Crimson Resonator". You can only use each effect of "Crimson Resonator" once per turn. You cannot Special Summon monsters from the Extra Deck, except DARK Dragon Synchro Monsters, the turn you activate either of this card's effects.








Red Dragon Archfiend
ATK:
3000
DEF:
2000
1 Tuner + 1 or more non-Tuner monsters After damage calculation, if this card attacks a Defense Position monster your opponent controls: Destroy all Defense Position monsters your opponent controls. During your End Phase: Destroy all other monsters you control that did not declare an attack this turn. This card must be face-up on the field to activate and to resolve this effect.
This is a tough matchup when you're behind, unless you have disruption like Nibiru. The key is to not let Bone Archfiend resolve, especially not to let him send Vision Resonator or Crimson Resonator to the Graveyard.
Some important tips:
Consider using Fiendess to negate Crimson Gaia . If you negate it when activated, it goes to the Graveyard, allowing your opponent to use another copy. But if you negate an effect, your opponent cannot use that effect again during the turn – due to the difference between "you can only activate 1... per turn" and "you can only use each effect... once per turn".
Hot Red Dragon Archfiend Abyss only negates effects, not activations. Therefore, it cannot negate Subterror Final Battle during the Damage Step, but Void Ogre Dragon can. You can use Final Battle's 4th effect to protect Subterror from Abyss .
If you use Final Battle outside of the Damage Step and get negated by Abyss , Final Battle will not be able to be placed face down again, meaning you lose that copy.
When deciding whether to call Umastryx or Ultramafus when going later, see if your opponent has Void Ogre and Abyss . Umastryx only removes 1 threat, while Ultramafus takes care of both. If you have Fiendess, your opponent won't be able to negate Ultramafus , allowing you to apply extreme pressure.
Nibiru is still the most effective handtrap, but Effect Veiler or Ghost Mourner on Red Rising or Bone Archfiend can also bring down opponents.
Salamangreat








Salamangreat Gazelle
ATK:
1500
DEF:
1000
If a "Salamangreat" monster is sent to your GY, except "Salamangreat Gazelle" (except during the Damage Step): You can Special Summon this card from your hand. If this card is Normal or Special Summoned: You can send 1 "Salamangreat" card from your Deck to the GY, except "Salamangreat Gazelle". You can only use each effect of "Salamangreat Gazelle" once per turn.







Salamangreat Balelynx
ATK:
500
LINK-1
Link Arrow:
Bottom
1 Level 4 or lower Cyberse monster If this card is Link Summoned: You can add 1 "Salamangreat Sanctuary" from your Deck to your hand. If a "Salamangreat" card(s) you control would be destroyed by battle or card effect, you can banish this card from your GY instead. You can only use each effect of "Salamangreat Balelynx" once per turn.








Salamangreat Miragestallio
ATK:
2000
DEF:
900
2 Level 3 monsters You can detach 1 material from this card; Special Summon 1 "Salamangreat" monster from your Deck in Defense Position, also you cannot activate monster effects for the rest of this turn, except FIRE monsters. If this Xyz Summoned card is sent to the GY as material for the Link Summon of a "Salamangreat" monster: You can target 1 monster on the field; return it to the hand. You can only use each effect of "Salamangreat Miragestallio" once per turn.







Salamangreat Heatleo
ATK:
2300
LINK-3
Link Arrow:
Top
Bottom-Left
Bottom-Right
2+ FIRE Effect Monsters If this card is Link Summoned: You can target 1 card in your opponent's Spell & Trap Zone; shuffle it into the Deck. Once per turn, during your Main Phase, if this card was Link Summoned using "Salamangreat Heatleo" as material: You can target 1 face-up monster on the field and 1 monster in your GY; the ATK of the first target becomes equal to the other target's, until the end of this turn.







Salamangreat Pyro Phoenix
ATK:
2800
LINK-4
Link Arrow:
Top
Left
Right
Bottom
2+ FIRE Effect Monsters If this card is Link Summoned using "Salamangreat Pyro Phoenix" as material: You can destroy all cards your opponent controls. You can only use each of the following effects of "Salamangreat Pyro Phoenix" once per turn. ● You can target 1 Link Monster in your opponent's GY; Special Summon it to your opponent's field. ● If a Link Monster(s) is Special Summoned to your opponent's field (except during the Damage Step): You can target 1 of those monsters; inflict damage to your opponent equal to that monster's original ATK.
Also a difficult match-up to go after. Salamangreat has good resource recovery, can dodge targets, and link monsters are hard to flip.
Even if you can't flip Link face down, you can still flip their other monsters face down to block them from expanding or calling Miragestallio .
It's hard to use Guru/Umastryx's effects without keeping Fiendess to negate Burning Shell .
If you can summon Umastryx, prioritize removing Gazelle to block play from the Graveyard.
Nibiru is still the best handtrap to go later. But Effect Veiler is still useful if you go first to block Gazelle or Miragestallio .
Predaplant








Predaplant Drosophyllum Hydra
ATK:
800
DEF:
2300
You can Special Summon this card (from your hand or GY) by Tributing 1 monster on either player's field with a Predator Counter. You can only Special Summon "Predaplant Drosophyllum Hydra" once per turn this way. If this card is on the field or in your GY (Quick Effect): You can banish 1 other "Predaplant" monster from your GY, then target 1 face-up monster on the field; it loses 500 ATK. You can only use this effect of "Predaplant Drosophyllum Hydra" once per turn.








Predaplant Ambulomelides
ATK:
1000
DEF:
2500
2 "Predaplant" monsters If this card is Fusion Summoned: You can add 1 "Predaplant" monster or 1 "Predap" Spell/Trap from your Deck, GY, or face-up Extra Deck to your hand. You can target 1 monster your opponent controls with a Predator Counter or 1 monster you control; Tribute it, and if you do, Special Summon 1 "Predaplant" monster from your Deck. You can only use each effect of "Predaplant Ambulomelides" once per turn.








Starving Venom Fusion Dragon
ATK:
2800
DEF:
2000
2 DARK monsters on the field, except Tokens If this card is Fusion Summoned: You can make this card gain ATK equal to 1 opponent's Special Summoned monster, until the end of this turn. Once per turn: You can target 1 Level 5 or higher monster your opponent controls; until the End Phase, this card's name becomes that monster's original name, and replace this effect with that monster's original effects. If this Fusion Summoned card is destroyed: You can destroy all your opponent's Special Summoned monsters.








Predaplant Chimerafflesia
ATK:
2500
DEF:
2000
1 "Predaplant" monster + 1 DARK monster Once per turn: You can target 1 monster on the field with a Level less than or equal to this card's; banish it. When an attack is declared involving this card and an opponent's face-up monster: You can activate this effect; until the end of this turn, that opponent's monster loses 1000 ATK, and if it does, this card gains 1000 ATK. Once per turn, during the next Standby Phase after this card was sent to the Graveyard: You can add 1 "Polymerization" Spell Card or "Fusion" Spell Card from your Deck to your hand.








Predaplant Byblisp
ATK:
0
DEF:
1900
If this card is sent to the GY: You can add 1 "Predaplant" monster from your Deck to your hand, except "Predaplant Byblisp". If a monster with a Predator Counter is on the field: You can Special Summon this card from your GY, but banish it when it leaves the field. You can only use each effect of "Predaplant Byblisp" once per turn.
This is a very favorable matchup for Subterror. Predaplant struggles against flip decks like Subterror or Ghostrick, often requiring Battle Phase or Knightmare Unicorn to clear the board.
Placing Predator Counter only works when they have no monsters. If you flip the monster at the right time, you can block their ability.
Dragotapelia only negates the effect, not the activation, so you can use Final Battle 's 4th effect to protect.
Two targets to negate: Fusion Recycling Plant (usually only played once) or Darlingtonia Cobra (effect can only be used once per game).
Most Predaplant decks play Lyrilusc - Ensemblue Robin , but it doesn't affect you because the summoning skill doesn't react and the flip afterwards is a Flip Summon, not a Special Summon - Robin can't be activated.
Hero








Elemental HERO Sunrise
ATK:
2500
DEF:
1200
2 "HERO" monsters with different Attributes Must be Fusion Summoned. Monsters you control gain 200 ATK for each different Attribute you control. You can only use each of the following effects of "Elemental HERO Sunrise" once per turn. ● If this card is Special Summoned: You can add 1 "Miracle Fusion" from your Deck to your hand. ● When an attack is declared involving another "HERO" monster you control: You can target 1 card on the field; destroy it.








Rainbow Neos
ATK:
4500
DEF:
3000
"Elemental HERO Neos" + 1 "Ultimate Crystal" monster Must be Fusion Summoned with the above Fusion Material Monsters and cannot be Special Summoned by other ways. Once per turn: You can activate 1 of these effects. ● Send 1 monster you control to the Graveyard; shuffle all monsters your opponent controls into the Deck. ● Send 1 Spell/Trap Card you control to the Graveyard; shuffle all Spell and Trap Cards your opponent controls into the Deck. ● Send 1 card from the top of your Deck to the Graveyard; shuffle all cards in your opponent's Graveyard into the Deck.
Worst matchup with Subterror. Almost impossible to win if you go later, unless you have a Super Poly counter Armed Dragon Thunder LV10 , Lord of the Heavenly Prison , or luck goes before .
If you don't unlock Fiendess + lv4 Subterror + Hidden City or Final Battle, you're very likely to get blown away. Only Hidden City will be destroyed by Thunder, losing the entire combo.
If you open all three, you can play Umastryx, negate Thunder with Fiendess, and still get cleared by Super Poly. In this case, at least you can combo with Guru.
HERO calls the field in 4 summons, so Nibiru is completely useless.
When going first, keep Subterror face down until the right moment, preventing Rainbow Neos from resolving, or wait until the Battle Phase to flip. Once your opponent has set, the risk of Super Poly is reduced.
Lord of the Heavenly Prison is extremely important in this matchup: protect Hidden City or Final Battle from being destroyed by Thunder. If they destroy Umastryx, you can use Final Battle to reset Umastryx, forcing your opponent to use Super Poly to remove it.
Conclusion
Subterror is a powerful anti-meta control deck that can disrupt combos, maintain an advantage over time, and has the ability to use tech cards that are difficult to play with due to skill restrictions. The gameplay is highly technical, with many micro-elements, suitable for those who like long matches, calculate the timing, and enjoy making their opponents "unhappy".