The Player Hides His Past - Chapter 8: Plain and simple

In a world fractured by conflict and haunted by shadows of the past, Kokushibo—the first Upper Moon demon—meets his end, only to awaken in a new life. Reincarnated as Crimson, a child born into a different family, he carries the memories of a past he cannot escape. Burdened by centuries of guilt yet indifferent to the present, he resigns himself to duty—until an unexpected bond with his newfound family begins to thaw his hardened heart. As he struggles between the weight of his past and the weight of the new life, Crimson must decide whether he will remain shackled to his former sins or embrace the possibility of peace.

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

A regular senior high school student accidentally obtained a Supernatural Ability System from three thousand years in the future. Lin Tian could exchange for all kinds of superpowers within the Supernatural Ability System. Exams? I have a photographic memory! You’re amazing? I transform into a Saiyan! An awesome life doesn’t need explanations!

Travel through Naruto and become the son of an ordinary civilian Chunin.

In this life-like world,

He obtained the golden finger to speed up the practice of ninjutsu,

Let ninjutsu itself produce a magical change from decay.

The knife cuts the jade, and the water bomb breaks Suzuo.

- Description from novelbuddy