Azathoth
From Multiverses
Azathoth is an entity trapped in Heartforge.
Appearance
Azathoth is reputed to look somewhat like a colorful void in the sky. However, it would be the last thing you would ever see.
History
Next to nothing is known about this entity. Any that attempted to observe it have never returned. Nobody knows why. A single written account described it as "moving, constantly fluxing, swimming in the sky...and angry."