Destroyer

Achieved by killing the Sky Eater.

You can get this ending by: Or just wait long enough till Sky Eater attacks you in Overworld and slay him.
 * 1) Activate all 5 monoliths
 * 2) Enter Hell through the stone arch
 * 3) Blow out the 3 blue torches in Hell
 * 4) Head to the Demon King's throne and slay him
 * 5) Choose to save the Overworld and slay the Sky Eater