21 parts Ongoing MatureY/n aka Four has been imprisoned her whole life due to the power she holds that she has yet to discover fully.
Her past is somewhat intertwined with the lives of Natasha Romanoff, Yelena Belova, Bucky Barnes, and Wanda Maximoff. Back when they were younger, in the Redroom and Hydra, Four had either briefly met with them or caught glances of them in halls passing by each other or being assigned to missions with them.
Years later after they had all escaped; Four was left behind and forgotten, kept a secret; stuck in the Redroom.
TW: SH