MTL - Urban Demon Slayer - Chapter 18 Mrs Rat, come on

You Liangxing would never open the speech function in game.
That was because his voice was…
Particularly! Kittenish!

But there was one day, he queued up with a teammate who had so much to say that they may as well explode. Vexed to the point of no return, he contributed a voice that was capable of splitting heaven and earth, “Don’t BB.”
The other party who was being scolded stilled. In the ensuing silence, he suddenly let out a long, relishing… Moan.
You Liangxing: “…..”

Later —
He realised that the person was a great god,
Much later,
Without him realising,
He became the great god’s royal healer.
…. And also his boyfriend.

- Description from Novelupdates

An ultimate warrior, the one and only Alchemy Emperor, Ling Han, died in his quest to achieve godhood. Ten thousands years later, he, with the ‘Invincible Heaven Scroll’, was reborn in the body of a young man with the same name. From then on, winds and clouds moved as he set himself against the uncountable geniuses of this new era. His path of becoming a legend has begun once more. Of all eras underneath the heavens, I am the strongest!

Volume 1 (Set between volumes 13 and 14)

A series of short stories set before the events of volume fourteen including how Team GROUP was formed.

Volume 2 (Set between volumes 16 and 17)

A series of short stories including two separate meetings between Touma’s and Mikoto’s parents, two tales involving two of the Level 5s of Academy City, and other funny stories involving some of the characters.

At first, when he learned that he was forced to go to many different routine worlds and be reborn into all kinds of cannon fodder, he was against it.

Because villains usually all only have a moment of satisfaction, the endings of cannon fodder are also frequently quite miserable.

But the man who gave him the system told him that this system not only has all types of powerful functions, but he can also break the routine lives of the cannon fodder. If he achieves this satisfactorily for each world, he can even become a god.

He’s already experienced over a thousand reincarnations, but hasn’t yet been a god. Since it sounds pretty great, why not just try it out.

From that moment on, he began the irreversible path of tyrannically oppressing people, while conveniently tearing open those white moonlights and so-called righteous people’s hypocritical masks.

His goal: wearing the villain’s role to walk other people’s righteous paths, leaving them no path to follow.

- Description from novelupdates