In JJK With Naruto Powers - Chapter 16: Lair of Curse Users

[The Demon King is Dead], a story in which the Demon King got immediately killed in the Prologue. I became the ‘Demon Prince’ of said novel.

…Help me.

Global evolution, the last phase of its arrival.

Being born with a golden spoon in his mouth, Jing Xia has had a smooth sailing journey. Having experienced three Beast Tides, exterminated those with S grade physiques, he never expected to die tragically at the hands of his blood-related younger brother.

Opening his eyes, he found himself back in the time before the end of the evolution!

What?!

You have a spatial golden finger?

Hehe, I have an invincible human-shaped lethal weapon!!!

A certain human-shaped lethal weapon: ……

- Description from Novelupdates

Xuanyuan was reborn into a strange new world where training to be a Xian was a cornerstone. There was however something ancient dwelling inside his body. He could now devour all of creation…

“I'm going out to do something, so I can't take care of you any more. You can go down the mountain and have fun. But if you can't find someone who matches your Innate Pure Yang Body in three years, you're finished!”These were the last words the old man, who was Lionel Yeager's teacher, threw to him before he vanished. Meanwhile, having mastered most of his master's skills, Lionel Yeager went down the mountain and took his first step into civilization for the first time in years.With his unparalleled medical and martial arts, he sets forth on a journey, befriending new allies and crushing all the enemies that stand in his way, as he attempts to resolve his Pure Innate Yang Body constitution, and cultivate to the top of the world!