MTL - Water Recovery System - Chapter 29

Ashen was a man from earth.His job?Nothing he just helped lonely women who didn't get enough love from their Husbands with his huge dragon of love.He didn't left any prey who he had his eyes on, whether it be Mom or daughter, all would be caught in his lustful hands.But after getting in an accident, he is reincarnated into a useless Prince's Body in a cultivation world.[Ding! Welcome Host I am the Villainous System]Ashen: “Villainous System? What is that?”[Ding! This world has innumerable protagonists but only few villains, therefore, to maintain the balance you have been brought into this world and I am here to help you in your journey]A sinister smile hanged on Ashen's lips as he muttered: “Doesn't that mean I can do all that I want”[Ding! No host, you are the useless prince now, You need to become powerful to do that]Ashen's smile retracted for a few second before appearing again: “Oh, I am a Prince? Then shouldn't I have a harem?”

When I transmigrated, the protagonist was already dead.Now, I have to protect the world after the bad ending.So first things first, I became the enemy of the main heroine, who was on the brink of ending her life.“I finally understand what all those things you said really meant.”“I’m like this because of you, junior. Take responsibility.”“I can only sleep when I’m next to you.”…But for some reason, everyone is starting to act a little strange.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

The strongest Demon Lord dies, and reincarnates as a human. Not only that, he because of various incidents turns into the hero’s best friend.

Follow his journey as he tries to help the hero escape his fate, and on the sideline to conquer the continent while he’s at it.