Joan of Arc
Joan's the legendary French military figure from the Hundred Years War—the one who basically became a symbol of resistance against English forces. But here's where it gets dark: being burned at the stake didn't kill her so much as break her. She came back wrong, driven mad by the experience, and now she's consumed by this burning desire (literally) to watch everything go up in flames.
She's an Offscouring now, which means she's fundamentally changed. Her Christian crosses have been inverted, and she's developed the ability to manipulate fire itself—pretty on-brand given her traumatic death.
There's something oddly self-aware about her too. She seems genuinely uncomfortable about her femininity, or lack thereof, though honestly it's hard to tell if that's her real hang-up or just another symptom of the madness that's taken hold. Either way, it's clearly eating at her.
Content compiled by AnimeList.moe from publicly available sources.