Leveling with the Gods - Chapter 10

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

Luca, killed by the Demon God, woke up to find himself back on the day the “Eternal Game” launched.At this time, the game has just started, and Earth hasn't turned into a monster's paradise; everything is back to the beginning.Determined not to let the tragedies of his previous life repeat, Luca, armed with ten years of gaming experience, re-enters the world of Eternal, only to awaken the unique SSS-level talent!Starting with maxed charm!As he enters the game, pondering how to enhance his strength.A cold voice suddenly calls out: “Adventurer, wait a moment...”

This novel is also known as I Possessed a Demon Sovereign

Chen Luoyang felt that something was wrong with his transmigration. After transmigrating, he possessed the body of the highest expert in the world, the Master of the Demon Cult, addressed respectfully as the Demon Sovereign.

Generally, aren’t supreme experts the ones that leave behind a wisp of their soul behind and occupy a new body of some miserable low-level youngster then they go on a journey of revenge and make a comeback?!

Or perhaps it would be transmigrating into a miserable youngster’s body and obtaining a cheat slowly walking the road to becoming a God?

But why did his transmigration seem wrong?

Now my environment is full of big shots and I feel like I’m going to be exposed!

- Description from Novelupdates