After Rebirth, The Real Young Master Began to Maintain His Health - Chapter 66

At the age of 12, Naruto Uzumaki gained the extraordinary ability to traverse between his home world, the Ninja World, and the mysterious world known as the Soul Society.Naruto's DiaryKonoha Year 63, March 15: I seem to have died [crossed out] I seem to have died and come back to life.Konoha Year 63, March 16: The weight of this new existence crushes him. A return to life offers no solace, and he questions whether it might have been better to remain dead.Konoha Year 63, April 1: Desperation sets in as Naruto searches the Soul Society for his parents, only to discover that this world is not connected to his own. His parents are nowhere to be found.Konoha Year 63, July: The dream of becoming Hokage fades, as Naruto finds himself detached from the village that once held his heart. The desire to become a Shinigami grows stronger within him, spurred by the hope of discovering the true Soul Society of his world and reuniting with his parents.

I found myself possessing the body of a young master who everyone was eager to kill. I’m invincible, so let them try to kill me. It’s only for one second, though.

She is a top-class spy, a poison specialist, but also a young and cute girl with a sinister temperament. In spite of her sweet and innocent appearance, she can complete any tasks without the slightest hesitation. One day because of an incomplete black magic, she was sent into the body of a girl who was deemed as a good-for-nothing. What kind of change will she bring to this continent?

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.