Dorwin Corvax

Dorwin Corvax was a human male who resided in Mustafar with his family in the days of the Old Republic. When the Sith invaded the planet in 3996 BBY, Dorwin was killed by the invaders.
Heartbroken, his wife stole the Dawnbringer, the most sacred artifact of the Mustafarians. She planned to harness its energy to restore her dead husband to life. Instead, it released powerful energies that turned the green and bountiful Mustafar into a hellish wasteland and transformed Dorwin into a Force Aberration, forced to exist in an estate between life and death.
In the following millenia, Dorwin became one of the biggest figures in Mustafarian mythology as The Black Bishop, god of death and sorrow. He usually appeared in front of people who lost someone close to them. In 19 BBY, he appeared to the Sith Lord Darth Vader shortly after the death of his wife Padme.
In 184 ABY, the spirit appeared to the young Sith Sheev Palpatine II, who managed to find the Dawnbringer and used it to keep his youth.
In 247 ABY, in the final battles of the Third Galactic Civil War, Daemon Sadryn, leader of the feared Adharii Order heard rumors about the Dawnbringer and planned to use it to resurrect Vrad Adharan. As only a member of the Corvax family was able to activate it, Daemon found a smuggler named Magnus Corvax and brought him to Mustafar.
A three-sided battle ensued between the Adharii Order, Sheev II and Magnus's Mustafarian allies, who wanted to destroy the Dawnbringer once and for all. The battle ended with Magnus destroying the Dawnbringer, finally freeing Dorwin of his curse and allowing him to die in peace. The artifact's destruction gave life back to Mustafar, allowing it to become a bountiful planet once more. Sheev managed to escape after the battle, finally fleeing the planet in which he was trapped for all his life.