Fou is the guardian deity of the Black Order's Asia Branch, sealed there generations ago by Bak's great-grandfather. She's not human, but she can shift into humanoid form whenever she needs to interact with people—or mess with them, which she does frequently.
She's best known for her "tough love" approach, especially with Allen. When she was training him to recover his Innocence, she'd attack him relentlessly, banking on the pressure to trigger his left arm's activation. But beneath that harsh exterior, she's genuinely caring. When Allen was down, she'd shapeshift into someone else like Lou Fa just to offer comfort without letting him know it was her.
Her ability to manipulate her form goes beyond simple disguises—she can transform her hands into axe-like weapons or copy someone's appearance entirely. She can also communicate telepathically. Bak gets the brunt of her teasing, though they're clearly close. She's shown she'd sacrifice herself for the people she cares about, and she proved it by taking Allen's form to fight a level 3 Akuma so the real Allen could escape. That battle left her badly wounded, though she eventually recovered.
The Asia Branch headquarters is wrapped in an incredibly strong barrier that Fou herself created and maintains—she basically functions as the barrier's living entrance.
Content compiled by AnimeList.moe from publicly available sources.
