One Harbinger HAS to die a villain and stay unplayable, who do you pick?

John Mihoyo has given you a choice. Every currently unplayable Harbinger will become playable, but you have to choose one who will become a central villain and die by the end, ruining their reputation forever and dashing any hopes of playing them. Who do you pick?

(No choosing any currently playable ones or Signora, her time is passed)