(Main world: Honkai Impact 3rd. The protagonist's power system is Dark Souls. He's Otto's actual older brother, not a half-hearted version.)
[Progression: Honkai Impact 3rd, 500 years ago -- Shakugan no Shana -- FP: Fragments of Silver -- Kamen Rider Build -- Honkai Impact 3rd game (major setting changes)]
In the world of souls, there are no sacrifices. The victors devour the souls of the defeated and take everything they possess, then continue down a more distant path, letting the weak witness alongside them the great deeds and sights they could never have achieved on their own.
Rising from the flames of chaos and exalted by the fires of existence, the scaleless white dragon does not fight for the world. It follows only its own desires and rules.
The black sun may cast its light, but never for the masses or the world. Its salvation and hope are meant only for a chosen few.