Crossover Anime: The Bull Demon's Road to Conquest

The labyrinthine ruins, silent for countless years, have welcomed a new master: Niu Kun, who inherited the title of King of the Bull Demons and Lord of the Beasts, and pushed open the giant bronze gate leading to countless other worlds and dimensions.
"Huh? Why are all these otherworldly worlds from anime I've seen before?"
Subsequently, Niu Kun wreaked havoc in the Apocalypse world filled with undead, became the King of Monsters in a mixed anime world that was both ordinary and extraordinary, became the Emperor in the war-torn world of Kill! Red, and served as the Demon God in the world of high school where demons and angels coexist...