Dragon Ball God Mu - Chapter 12

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

Zhou Donghuang, a man from the Earth, is able to destroy any planet in the universe without lifting a finger. His supreme will can sweep across the vast cosmos in the blink of an eye. And his immortal spirit can depart from his body and wander around the universe!

We attend school, find love, work, buy a house, pay our housing loans, insert weird faces in WeChat, watch movies… do any of you find anything amiss? One day, a group of strange people entered this world, equipped in strange clothing and possessing extraordinary powers, cold-blooded killers! They call themselves [Players].

My childhood friend went to the academy.