Kamen Rider: You Transform, I Mutate

[A shared universe combining Kamen Rider 555, Kamen Rider Ryuki, and Kamen Rider Build] Reborn in the world of Kamen Rider, he has terminal bone cancer from the start. At death's door, a monster burrows into his body and becomes his symbiotic partner. His cancer is cured, but he gains powers that no human should possess. He helps people fight monsters, but the Riders turn around and try to kill him. He approaches the monsters to negotiate, but they want his life. Xu Zheng looks at the people hunting him from both sides and smiles. "Fine. If neither side will have me..." "Then I'll be your third enemy." Before the story begins: "I have to survive." After it begins: "Come at me all at once. I'm in a hurry."