Nerull was the first god of death, darkness, murder, and the underworld. He was known as the Reaper, the Foe of All Good, the Hater of Life, and the Bringer of Darkness.
During the Dawn War, Nerull introduced Necromancy to the world. Despite protests from the other Gods, he entrusted his angel, Sindatari, with the secret, who then passed it to Vecna, a mortal at the time. Vecna used this forbidden magic to raise the dead, creating an undead army to aid the Gods in their war.
Horrified by this defiance of the natural order, the Gods banished Nerull to the Shadowfell, sentencing him and Sindatari to eternal exile. Stripped of his place in the Compact of Heaven, Nerull became an outcast, his legacy forever tied to the dark art of Necromancy.
Nerull’s Death
Nerull was trying to use the souls of the dead to rise to the position of Overgod. He trained his queen, in the use of the power gained from the souls of the dead. This proved to be a tactical mistake, as the Raven Queen led a rebellion of tormented souls and slew Nerull, and claimed his portfolio. Though her body died as well, due to her power over souls she managed to hold onto existence, and claim the mantle of the slain god of the dead.