Souls Online: Mythic Ascension - Chapter 285: The Heartwood Tree

He is an undead who is devoid of all humanity, he is the one and only supreme overlord, he is a man who has severe mysophobia.

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

“Transmigrate as the Final Villain of the novel...” Ark stared at his reflection in the mirror he held. It was Theos Von Fallen, the final villain of his favorite novel.Although he was the final villain and the strongest in the novel, he was killed by the protagonist and his harem in the finale.[Ding. The Heroine Snatching System has started] Ark gave a crooked smile when he read the system message in front of him... “Exchange!” he shouted, unwilling to accept the fate they had in store for him.Trapped in the world of his favorite novel as the most “evil” and powerful villain, Ark, now Theos, will use his knowledge as a fan obsessed with the novel to take away all the protagonist's opportunities.Whether he can become the focus of the whole show or whether a script will dictate his fate, he will decide! He will live as a true villain who doesn't care about anything but his life and his loved ones.

A continuation from where High School DxD Volume 25 left off.