_Type:_ YoRHa O-Type (Operator model)
_Affiliation:_ YoRHa Soldiers
_Height:_ 167 cm
A messenger who delivers orders and instructions from headquarters to the active YoRHa Soldiers on the ground. 21O is in charge of supporting 9S. She has a calmer and stricter personality compared to [6O](https://anilist.co/character/289475/Operator-6O).
