The Undying Mecha Emperor - Chapter 6 Emperor Justin

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

Xu Yuan transmigrated to a parallel world where everyone became lords. Initially, he thought he would be a lord too. To his surprise, he became the Dark Demonic Dragon, a starter hero awaiting to be summoned by a lord. He also awakened the Dragon God Cultivation System.

[Transformation of the Dark: You can level up quickly by staying in the dark.]

[Slumber of the Dragon God: For the Dragon God, sleeping means residing in the dark.]

[Rejuvenation of the Demonic Dragon: You can revive using the power of the dark. Your basic attribute points will increase every time you revive.]

[The Blade of the Hidden Wings: This is a dark attribute AoE skill. It can annihilate all enemies within the area of effect.]

[Unlimited Devouring: The skills of your enemy shall be yours now. Unleash this skill to devour your enemy and acquire their skills.]

…

Su Wan, a beautiful lord, had no doubt that she could easily become the most powerful lord in the universe.

She felt her heart beating fast when she first saw her starter hero dazzle amidst the flashing summoning light.

Unbeknownst to her, her nightmare was about to unfold.

While other heroes devoted themselves to training day and night in order to level up, her hero goofed around and showed no effort to improve himself.

While other heroes charged into the enemy’s base and valiantly killed off their foes, her hero hid in their base and slept soundly.

…

As time passed, Su Wan slowly discovered that there was more to her hero than met the eye.

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.