A Reincarnated Mage's Tower Dungeon Management - Volume 1, Chapter 7 – Dungeon = Butt on the Wall?

The villainous young master Dark Demon finally recalled the memories of his previous life at the sorting ceremony of the Dueling Academy. He was reborn in a very strange Galgame world.

And he was the ultimate villain in the game, the Demon God of Seven Original Sins!

Superbia、Invidia、Ira、Accidia、Avaritia、Gula、Luxuria！

Once any one of these seven indicators broke through the critical value, he would irreversibly transform into the Demon God!

In the era of Saint Marian, where the demons had been completely destroyed and the demon king had fallen into eternal sleep, no heresy was allowed to survive!

An 18-year-old poor college student tried to apply for a job as a tutor but his life almost ended as demons' meal. In his last breath, a mysterious woman gave him a strange power. When he opened his eyes he had turned into a demon with a system that would turn him into… A pervert.

Now he must lived with his dual identity as a model student named Ethan and an incubus named Damian.

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