Resentment

A tiefling who was kidnapped and forced to go through experiments and surgeries to quell her "masters" curiosity

Her wings were forcibly torn off and stitched onto Kairos, their legs were swapped, and one of their eyes were swapped (hers were originally purple, but she was given one of Kairos' red eyes and vice versa)

she escaped that place with a new name and a newfound rage, she sought the power to take revenge on her captor and a powerful patron took notice of her hurt and anger and decided to make a pact with her (for a cost, of course. she has to do bad things in return but she sees it as worth it. She isn't evil per se but she does have a very warped and twisted mind and is easy to manipulate in that way by someone promising her power and revenge)

Character sheet