Carmen is introduced in No Mass as Elena’s classmate and best friend who Penelope had never met before. She maintains a gloomy disposition and a goth appearance. Carmen has two brothers, a priest and a witch who are very scary. One of them lives in Austin, Texas. In Strays, it is revealed that her parents have been deported to Mexico. She was sent to live in Austin, Texas after her parents were deported. She keeps in contact with Elena via video chat. She surprised Elena by returning for her quinceanera.