I Have the Alchemy Emperor in My Head - Chapter 30

On the will left behind by the 14 year old suicide victim K:

“Taku Sugawara is the devil. Nobody should believe his words.”

I am Uchiha Shirou! I represent all bloodline families in the Shinobi World. This is a world that values the power of bloodlines!Under the true Will of Fire, the rise of Konoha has brought about an unprecedented revolution in the entire Shinobi World!Studying medicine won’t save the Shinobi World!This is the story of my struggle!

Kael, a reclusive and antisocial man, died alone in his apartment, consumed by frustration and regret. But his tale didn't end in darkness. Reborn in the unforgiving world of Eridoria, where the law of the jungle reigned supreme and apes were eerily absent, Kael found himself in the body of a lion cub with a unique bloodline.This was no ordinary rebirth; he was a lion unlike any other. Thrust into the complex web of pride dynamics and social hierarchy, Kael must navigate treacherous alliances, rivalries, and his own primal instincts. With a fierce determination burning within, he sets his sights on a singular goal: to claim the title of the ultimate King of Beasts.Warning: R18, incest, harem, neutral MC, violence.

An ordinary student, a wretched peeper, a cowardly teenager with a kind heart. In a terrorist attack, he inherited the knowledge of countless elites, embarked on a path of God Jagged Tu…

He is an artist!

He is a mathematician!

He is a psychology Doctor!

He is a master of fighting!

In fact, he is a man

Taken off raw site:

A wretched, dirty young man is working during the summer when he was caught up in a mysterious explosion. After that explosion, the young man is then left with the memories and knowledge of dozens of the world’s experts.

He has changed, his heart has become cold, iron-blooded. He became a killing machine, his mind turned mechanical, calculative. Everything goes according to his plans and calculations!

In this magical, slaughterous world, a door is opened for him…

- Description from Novelupdates