The Darkness

The Darkness was the result of a black magic spell cast on Illsyore.

This spell merged the other dungeons in Illsyore's body into one.

The Darkness wanted control of Illsyore so that they could destroy the world.

Mentioned/Appears:
The Darkness is introduced (as separate dungeons) in Arc 3 chapter 24.

The dungeons are merged into the darkness in Arc # Chapter # [can someone find out pls]

The Darkness is destroyed (read: merged with Illsyore) in Arc 5 chapter 81 Part 2