"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.
|The Hidden City||Shambhala|
The effects of the two "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 is 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.
Flipping the "Subterror Behemoth" monsters face-up and face-down can be controlled through card effects such as "Prediction Princess Tarotrei", "Book of Taiyou", "Subterror Final Battle" and "The Hidden City".