MTL - Let Me Shoulder This Blame! - Chapter 68 Silent creator

The MC (Minato) is a college student who died in a plane crash and was reincarnated in a fantasy world. He was raised alone in the wilderness by his succubus mother, and now he tries to make his way as an adventurer.

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

When a person dies, they either die light as a feather (aka unimportant) or heavy as Mt. Tai (aka very important).

At six, Jiang Huai stubbornly clung to the thighs of the fairy in white and wouldn’t let go. She took him back to the mountain and made him her only direct disciple.At fifteen, he changed his way of addressing his master from ‘mother’ to ‘sister,’ and after being severely beaten, he corrected himself to ‘Master’. Jiang Huai harbored a grudge in his heart for a full six years.At twenty-one, he learned how to talk back to his master.