Black Soul

Black Souls are variants of the Willowisp. They are the largest Willowisp variant, standing at eight feet tall. They are the spirits of evil beings who died searching the swamps of Kurast for dark, lost secrets of power.

In-Game
They are unused, and were most likely supposed to be in Chaos Sanctuary. They have a 90% chance to deal Mana Burn with melee. There is an Guest Monster based on them.

Development
Black Soul was named Hell Spark at some point of development.