Lokirk

The first Demon. Lokirk is incredibly powerful, as he was the first to be damned by Pharom. Lokirk essentially set the bar for what is the farthest a mortal will be allowed to get.

Before the Lokirk Era, but after Dungeon Era, Mendrin Vishwanath attempted to summon Lokirk to the Material Plane. This was prevented by Belial O'Gaffney, which consequently caused the later to become a demon.