One Piece: Don't Worry, I'm a Doctor - Chapter 263: Spar

This is a ‘rebirth’ story where Chen Rong, the heroine, finds her second chance at life after burning herself to death. Set in the Eastern Jin era when bureaucrats and their lofty yet equally hypocritical and oppressive ideas once ruled the empire, Chen Rong is made to use her past life’s experience to survive and hopefully find happiness this time around.

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!

With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

Gods and demons fought, the worlds collapsed, only eternal immortal realm, lasting in the world.

After eternity, a god of war named Zhao Yun condensed the heavens and the earth, recast the cosmos, from the blue to the earth, marked the eternal immortal realm, in the name of the god, the king is over the world.

Since then, what he said is a myth.

- Description from MTL

Just like how everyone adored heroes in their childhood, a certain young man adored those powers hidden in shadows. After hiding his strength and living the mediocre life of a mob character by day while undergoing frenzied training by night, he finally reincarnates into a different world and gains ultimate power. The young man who is only playing at being a power in the shadows, his misunderstanding subordinates, and a giant organization in the shadows that gets trampled…. This is the story of a young boy who had adored powers in shadows possibly eventually reigning over the world of shadows in another world.