Plot-oriented + with a knife + the protagonist is both good and evil + there is a female protagonist

PS!!! You need some IQ!

Timeline: Came to Teyvat with Yingkong, woke up with Kong in the Kanreya era, challenged Tianli alone, was defeated and died, was taken away by the Queen of Winter and his body was revived, but he lost most of his memories and became the 0th executive of the Fatui [The Dead].

Japanese light novel + not invincible + daily life + redemption + slightly supernatural + Taoism + alchemy

Hoshino Gen traveled through time, had a sister, a house, and busy parents.

With busy and wealthy parents and his only sister being a super popular idol, there is no doubt that Gen Hoshino is a winner in life.

But that—

In the dilapidated gym under the setting sun, a swordsman who has been guarding for hundreds of years with a sword...

In the warm and healing game, the Lolita dress stained with blood...

In the abandoned old campus, the past is buried by weeds...

On the empty stage, there was an inexplicable and strange singing voice...

Someone has to find out.