The right Shinobi
To wake up in an unknown place, get a sensory shock from the abundance of other people's memories, and in the end also realize that you are now locked in a child's body, whose name you even know too well… For many, such a sudden development of events can turn out to be hell and cause endless regrets.
For many, but not for someone who is completely sure that his past body is dead, and a new, completely healthy and literally bursting with life body is perceived as a real gift and, one might say, a dream of the last years of his past life. And it's also an opportunity, an opportunity to live another life in a much more interesting, even dangerous, world… Moreover, you already have some knowledge about this world. And plans for a newfound youth can be built simply grandiose.