Haeresys

Haeresys is an underground arena of the Fatui which appears in the manga.
This arena is used for experiments where captured test subjects are brought to fight unknown creatures. Il Dottore and Krupp performed experiments here on Contender 139 Anthony.
==Trivia==
===Etymology===
* is a Latin word meaning "sect" or "heresy," derived from the Ancient Greek word .
==Other Languages==
ja:ヘレシス