The Anti-Chapel is an upside down version of the Royal Chapel in Castlevania: Symphony of the Night. It is the same as the Forbidden Library, a comforting, blue aura has descended upon all.
The Anti-Chapel can first be reached from the left from the Reverse Keep. It proceeds upward roughly diagonally to the left, with exits to other stages along the path to the left, including Death Wing's Lair, the Reverse Colosseum, or the Necromancy Laboratory.