Mary

Mary is a medical Nikke who is a part of the Seraphim squad along with Pepper. Mary is often seen as a gentle and caring woman who earned the nickname "White Angel." However, those who don't listen to her medical advice when recovering often see a darker side often referring to this side of her as the "Black Devil." In the past, Mary was a doctor even before becoming a Nikke. However, Mary started feeling bad for patients she couldn't save. This led to her making her patients suffer in order to sell their brains to later become Nikke's. Pepper, who was also a nurse when she was a human, witnessed Mary's actions and horrified and eventually pushed Mary down a flight of stairs, claiming Mary's life. Feeling terrible for her actions, Pepper asked to become a Nikke and had her memories erased and began working with Mary, who was also turned into a Nikke. When Mary first woken as a Nikke, Mustang, the CEO of Tetra, was the one who turned her into a Nikke but didn't erase her memories, making her suffer like her previous patients. Feeling guilty for her actions, Mary fully dedicated herself to saving as many lives as possible.