Harry Potter: A Certain Ancient Rune Professor of Hogwarts (TL) - Chapter 654

Crossing to One Piece world, he became Roger’s younger brother.

Unexpectedly, Gol-D-Roger who was in his fifties had a teenage brother. But he was so weak.

Fortunately, at the age of sixteen, he actually found himself with a possession soul system.

He had attached to the master IP man, also to the White Phoenix and to Ge Nie with his strong ability of the Hundred Step Flying Sword.

If you think that he can only Purchase these? Then you’re wrong!

Pain, Itachi, Ichigo Kurosaki, as long as there is money, any soul can be Purchased.

- Description from Novelupdates

“Seven years later, she returned with her baby

”Give me the child, and you can name a price!“

”Spring only sows the seeds. When it comes to autumn, you want to obtain a son. Heh, man, aren't you thinking too simply!“

”If you want me to call you daddy, then you have to show your ability to chase after my mommy. The man that my mommy likes is my daddy! “Otherwise, there's no need to talk about it!”

“Isn't this the weak young master of the Valhalla family?”“Hahaha! I heard he only knows how to waste money... Completely useless.”Another voice, dripping with false pity, chimed in.“Both his sister and brother are Tamers, strong ones at that. While him... the eldest... pathetic!!”The final word, spat out like a curse, hung in the air: “Useless!”In this world, where the bond with powerful Beasts dictated one's standing, where strength was synonymous with the ferocity and strength of your companion.Christopher Valhalla was an anomaly. He found solace not in the thrill of battle or the acquisition of monstrous power, but in the simple, fleeting joys of life. He enjoyed partying, clubs, and women.He offered no retort to the cruel rumors that trailed him like a shadow. Because, truth be told, a knot of fear tightened in his stomach at the mere sight of the majestic, often terrifying, creatures that others commanded.But every life, regardless of its perceived worth, eventually finds its end. For Christopher, it came not in the jaws of a wild Beast, nor in a duel he was ill-equipped for, but in the insidious grip of a rare and incurable sickness.Some days later his flame flickered and he died, leaving behind a void filled with the echoes of scorn.Yet, where one life ended, another began. In the silent stillness of Christopher's vacant shell, a new consciousness stirred. A soul, bearing the weight of unmatched power and a reputation that sent shivers down the spines of even the most formidable Tamers, had arrived.This was the Supreme Tamer, a legend whispered in hushed tones across the world, a force of nature who had inexplicably perished at the hands of betrayal.Given this unexpected second chance, the Supreme Tamer, now inhabiting the frail form of Christopher Valhalla, felt a strange sense of acceptance. He looked upon the unfamiliar yet familiar faces of his new family – the concerned worry etched on their features – and a flicker of something akin to kinship sparked within him.A silent vow formed in his mind, hardening into an unbreakable resolve.The rumors that clung to this body like a shroud would be torn away. And the five Master Tamers who had orchestrated his demise in his previous life… They would learn the true meaning of fear.Their betrayal would be answered, not with petty revenge, but with the full, terrifying might of the Supreme Tamer, reborn. The world was about to discover that “useless” could be the most dangerous disguise of all.

A biker tries to save a cat on the highway and gets hit by a truck (Truck-Kun), he was rushed to the hospital but, due to internal bleeding, he dies only to be reborn as a cat, in a new world with a system.

In this new and vast world, he tries his best to get used to his new body and get stronger along the way. With his overpowered system and skills. To one day become untouchable.