Harry founds a mythical, ancient japanese broken katana and upon touching it he dies and his soul is merged with the soul of the last person that wielded the sword, Miyamoto Musashi. He can only speak japanese now. Using the diabolic powers of the Yomi sword he reaps the magical world of evil, slashing for all he is worth. He needs not magic anymore. He is magic. He saves Fleur's life and a soulbond is formed, but because of the nature of his fractured soul their souls merge instead of merely bonding. They are now one three souls sharing a single body, and no one can stop them.
There you go. A trash prompt to balance things out
DavidTheAthenai