Timothy Hearst is a small boy carrying a mysterious ball embedded in his forehead—a jewel his father, a jewel thief, forced him to swallow years ago. The jewel gave him an unusual ability: he can take over other people's bodies at will.
Best known for operating as "Phantom Thief G," Timothy used this power to steal from Paris's wealthy collectors and museums, funneling the stolen goods to fund the orphanage where he lives. It's a Robin Hood situation, though obviously one that catches up with him eventually.
Everything changes after a traumatic run-in with an akuma and a close friend. The incident awakens his Innocence—a weapon of the Black Order—and Timothy discovers his true power is Divine Possession, far more potent than his thief abilities. When the akuma attack reaches the orphanage itself, threatening the children and his teacher, Timothy makes the choice to join the Black Order for their protection.
He does this on one condition, though: the Black Order has to cover all the damage he caused during his phantom thief days. Komui's not thrilled about that demand, but Timothy's serious. After officially joining up, he becomes Cloud Nyne's apprentice.
Content compiled by AnimeList.moe from publicly available sources.