Honkai: Starting as a Ghost Girl from the Previous Era Before the Night Battle

Wu Ye transmigrates into the world of Honkai, but something is off about it. Whenever night falls, he is dragged into a world called the Interlude, where all the dead transform into ghosts and monsters and attack the living. A bride in red, Elysia; a green-haired snake demon, Mobius; a cold-hearted snow maiden, Sakura; the bloodstained saint, Cecilia... The uncanny creatures cannot be killed. They must be purified with overwhelming yang energy (right behind you, Divine Might). Purifying each female ghost grants stat and item rewards. After doing so enough times, he can even bring the ghosts into the real world to help him fight and train.

Then one day, Wu Ye earns the chance to be promoted to an executive of World Serpent and is sent to the Elysian Realm for training. The person who greets him is none other than the pink-haired girl he's killed countless times in the Interlude, Elysia.

"You've finally come, Mr. Wu Ye, after doing so many unspeakable things to me in your dreams."

"Welcome to the Elysian Realm."