His Darkness or the Dark God of the Dasati was a montrous bloated creature of The Void: a Dreadlord. Thousands of years ago he found a way to pierce the walls of reality and enter the Second Circle having come from the Third Circle. Once there he supplanted Bakal the Dasati God of death & set about disposing the other Gods. This done, he went to sleep at the heart of Omadrabar and influenced the dreams of the Dasati, twisting them into a race of fierce warriors who worshiped death. He resides in a huge pit in the Temple of the Dark Heart on Omadrabar where he squats in an orange lake of Dasati blood. He is fed by his Deathpriests who throw victims in for him to consume. He also devours the life energies of anyone who dies on any of the twelve worlds.
When the portal was opened between realms opening the way to Kelewan, he used his mystic energy that he had been hording for centuries to lift himself up from Omadrabar to Kelewan. As he was moving up the tunnel, Nakor who had been hiding on a ledge overlooking the pit, flicked the Godkiller after His Darkness. As it flew, the Godkiller drew the energy of the portal after it, sealing the portal behind His Darkness so he could never return to Omadrabar. Meanwhile on Kelewan Pug had lifted himself high up into the atmosphere, and using a powerful spell he created a rift in space in front of the moon with the other end opening just on top of the Black Dome where His Darkness was about to enter Kelewan from. The moon struck the rift in space and a shard the size of a mountain was forced through the rift & into the Black Dome. In the same instant the Godkiller and the moon shard struck His Darkness crushing him and obliterating Kelewan at the same time. It was revealed to Pug by Banath that His Darkness was destroyed, or as he put it, cast back to The Void, never to return.