Soulis is the guardian of the Soulsborne Geode, when killed, he respawns at the nearest pyre, he rests at a cathedral where the pyre of the saint’s flame is located at. Without the saintly flame, the night engulfs him, and he becomes empty. He wields the Dark Lunar Greatsword to hold the night from beginning its reign but it is merely a matter of time before the night escapes.
(The Soulsborne Geode is a stone that controls and can harness all souls)