Technically, a god, celestial, or cosmic being is immortal and cannot die. But if they were cursed with dark magic of primordial time, that would be another story. Lucan was once a celestial knight who protected all plane of existence. Betrayed by another god and struck with a powerful curse and became a wraith who not living or dying. Made him fall from grace, and he can't feel the celestial light anymore.
With corruption curses inside him, it turns his holy light into dark power. Every swing of his sword now can cut the through the light and burn the holy itself. The perfect power for fighting and destroy another celestial being.
He has become the embodiment of vengeance and hatred, and joined the rank of "Knights of the Dark Order", The most elite warrior of Dark Lord.
Faction "Cult of Dark Lord"