Naruto: Konoha's Kanpu - Chapter 31: What Kind Of Trash Are You?

In a world where 70% of the population possesses powers managed by a LitRPG chip, Kang Ji-Hoon, a timid young man, joins the prestigious Apex Academy to save his sick mother. Ranked last at F with his seemingly useless ability to summon a dagger, he becomes the target of relentless bullying. Pushed to his limit, he unleashes the true power of his weapon, a dark and destructive force. As he transforms into a ruthless anti-hero, a cosmic threat emerges to assimilate humanity. Ji-Hoon then realizes his dark destiny: to save everyone, he must destroy everything.

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

Ning Yechen used to be the Demon Lord. He singlehandedly took over the Demon Realm and attacked the Heavenly Realm. His name preceded him throughout the Six Realms. He got tired of fighting, so he quietly went into seclusion and became a happy hermit.One night, an Empress from the Heavenly Realm fell into the Mortal Realm after someone drugged her with an aphrodisiac. She inadvertently fell into his room, and they made out. After the deed, the Empress quietly left. Just when he thought he would never see her again, she showed up in front of him ten years later, bringing a child, saying it was his daughter and demanding accountability from him! “She’s your daughter. You have to be responsible for us!” Ning Yechen was stunned!

What?! The sticking to her daily, eating her tofu (taking advantage of her ) is a cross-dresser?

Not to mention that he is the Evil Highness!! She had slept beside him, and was touched by him, what a big loss!

Ah–!

Softly on his chest, listening to his pounding, strong heartbeat, her face turned red. Her greatest desire was to be in his arms.

She never dared to dream before, dared not wish for, and thought that in this life there was no such chance. This had been in her most secret heart of hearts, she longed for his warmth, longed for his love.

Even though he had hurt her before, he had given her more tenderness than others.

Being teased, loved, laughed at… had infiltrated into her bloodstream. Love, she did not know when it had taken root, for when she discovered it, it had grown into a towering tree, no longer able to be split open or cut off.

His hug, his warmth, she would not allow him to give it to others. If they were not only for her, she would rather not have them.

- Description from Novelupdates