"Subterror" (サブテラー Sabuterā) is an archetype of EARTH monsters that first appeared in The Dark Illusion. It is one of two formerly TCG-exclusive archetypes that premiered in that set, the other being the "SPYRAL". The archetype includes a sub-archetype called "Subterror Behemoth".
All members of this archetype are EARTH monsters with various Types.
The high-Leveled "Subterror Behemoth" is comprised of colossal beasts whose names are a reference to subterranean anomalies or types of rock (TCG), or points and portions of the Mediterranean Sea (OCG). The low-Leveled "Subterror Nemesis" monsters are human hunters fighting the "Subterror Behemoths".
"Subterror Behemoth Fiendess" is revealed to be "Subterror Fiendess" and "Subterror Guru" is "Subterror Behemoth Speleogeist", respectively.
|5||Sea Serpent||Stygokraken||Aquadria|| Stygofauna|
Sea of Sardinia
Strait of Gibraltar
|12||Pyro||Ultramafus||Balesash|| Volcanic ultramafic rocks|
|The Hidden City||Shambhala|
|Subterror Behemoth Burrowing|
|Subterror Cave Clash|
|Subterror Final Battle|
The effects of two of the "Subterror Nemesis" monsters are very necessary in order to Special Summon the "Subterror Behemoth" monsters from the Deck face-up or face-down. Since "Subterror Nemesis Warrior" has the ability to be continually re-used, it was common to see the cards "Speedroid Terrortop" and "Speedroid Taketomborg" being used to Xyz Summon "M-X-Saber Invoker" simply to search it out. "Tour Guide From the Underworld" with any Level 3 Fiend-Type monster or "Predaplant Ophrys Scorpio" with "Predaplant Darlingtonia Cobra" can have the same result, with the ability to search "Instant Fusion" if using the "Predaplant" engine, although "Invoker" is now Forbidden.
The effects of the "Subterror Behemoth" cards can be used to Special Summon themselves in face-up Defence Position if a face-up monster you control is flipped face-down, provided the player controls no face-up monsters. They can also flip themselves face-down once-per turn, allowing the player to Special Summon as many they have in hand once one is Summoned. However, getting one on the board is the usual struggle for a conventional "Subterror" deck. Cards like "Nemesis Warrior" have unfavourable card advantage just for a single unsupported monster, while off-archetype cards like "Back to the Front" are too slow. In addition, the requirement that there is no face-up monsters is tricky at best when playing with off-archetype monsters or Link Monsters, ironically including the Deck's Link "Subterror Behemoth Fiendess", making the Extra Deck normally inaccessible. Such versions of the deck are playable, but not at high level.
Flipping the "Subterror Behemoth" monsters face-up and face-down can also be controlled through card effects such as "Prediction Princess Tarotrei", "Book of Taiyou", "Subterror Final Battle" and "The Hidden City". In particular, "The Hidden City" can start off many of the Deck's best combos by searching a "Subterror" monster, flip a monster the moment it is set, and flip monsters to block attacks. This speeds up the Deck somewhat, and in some cases allows them to be unexpectedly used to interrupt the opponent's turn. However, most of the Flip Effects of the Deck are hard once per turns, preventing them being spamable by repeated use of these effects.
Since the release of "Subterror Guru", an unexpected change of tack for the Deck has proven highly effective. "Guru" is a Level 4 Flip monster, allowing it to be Normal Set, that searches any "Subterror" card on flip. While it is face-up on the field, it can flip itself and any other monster face-down, an effect that becomes a Quick Effect if the player controls another "Subterror" card. It combos extremely well with "The Hidden City", being searchable and immediately flip-able by it. "Guru" can then search "Subterror Fiendess" a hand trap that can negate the activation of any card or effect by flipping a "Subterror" monster face-down. These 3 cards combine so well, it's well worth building a whole Deck dedicated to it, known as "Guru Control"."Subterror Final Battle" can pitch in both by helping speed up flipping "Guru" or raising the ATK and DEF of "Guru" to obscene levels. The fact it Sets itself instead of going to the GY allows it to repeatedly use these effects over and over, with the resulting damage output giving this deck an easy win condition not normally seen in control decks. "Guru" can also Chain its second effect to it, adding a degree of surprise disruption to it. "Subterror Cave Clash" is normally used at 1 copy, since it is always accessible through "Guru", and it adds some extra ATK while recovering "Fiendess". It also adds versatility to "Guru"'s second effect. Finally, it is well worth playing a copy of "Subterror Behemoth Umastryx" for its powerful banish effect, and easy searching/Summoning. Other "Behemoth"s can be experimented with, but "Umastryx" has proven itself the most versatile and powerful.