The Game's Extra: Azhriel Odyssey - Chapter 41: Cute.

Bai Yang is the youngest son of a rich family, he grew up spoiled and unambitious, and no one expects anything from him. He doesn’t really mind this though, because he’s still able to live a simple and happy life.

One day, however, his older brother got into an accident and is now comatose. Bai Yang’s father now has to consider his youngest son to take over the family business. Unfortunately, for him, Bai Yang is a weak, timid, and cowardly child. How can he ever succeed?!

Wanting to change his son’s personality, his father has Bai Yang transmigrated into the world of Wild Wind, a very famous fantasy novel. Bai Yang’s father hopes the environment of that world will shape his son into a more arrogant and domineering man, as a child of a wealthy family ought to be.

However, due to an error in the Main System, instead of transmigrating as the protagonist, Bai Yang ends up becoming a cannon fodder villain, Xie Zietian, from the Demon Realm! In order to safely and quickly return to his world, Bai Yang has to ensure that the protagonist, Zhou Ying, ascends to the heavens so his transmigration mission will be completed.

In order to sneak into the Human Realm and help Zhou Ying, Bai Yang comes up with a variety of excuses to the Demon King of Everlasting Night, such as…

Bai Yang said in a dignified manner, “Your Majesty, that person might threaten the demon world. I will go to the human world to kill him for you!” (Actually, I went there to meet the protagonist.)

Bai Yang proclaimed his loyalty to the Demon King, “Your Majesty, hang in there. I will go to the human world to find the elixir for you!” (Actually, I went there to save the protagonist.)

Bai Yang said with an attitude of selfless dedication, “Your Majesty, I just want to go to the human world to further your great cause!” (Actually, I went there to see the protagonist.)

The Demon King’s face remained impassive but, in fact, the tips of his ears were red. He was thinking: I can’t believe he loves me so deeply…

Demon King said, “Humph! Seeing how clingy you are, I’ll accept your love. Tell me! Whatever you need, I’ll give it to you!”

Bai Yang: “What the hell…! Your Majesty, I don’t love you.”

Demon King said, “No, you love me.”

The Demon King truly believed Bai Yang and him shared a deep mutual love until he discovered that Bai Yang was having an “affair” with a “wild human” …

- Description from Novelupdates

Reborn and returning, he possesses medical skills, can practice immortality, has a slave who is the king of killers, and a maid who is the school beauty pursued by everyone. Even casually taking out a piece of trash can shock the world. His return has set this world ablaze.

“You’re the moonlight that lights up the night’s darkness~

Ding![The Host has died!]A system message popped up in front of Nell's body after his last dying breath.Ding![Dark Evolution has been activated to absorb the death essence of the host.]And then he opened his eyes to find himself in the past right before the battle started.'Ah! Am I back to the past?'Ding![Please choose a partner to start the Dark Evolution process.][Partner Condition: Must be a living creature from the Monster category, not the Human category][Partner Gender has to be Female.]'Partner? A monster?'Nell's heart pounded in his chest, and he felt a cold sweat coming on.'A female monster?'