Sofia serves as personal maid to Faye Carver in the affluent Carver household during a historical period resembling the American Civil War era. Her background traces to childhood, taken in by the Carver family alongside John. She grew up closely with Faye as a cherished companion rather than merely a servant, fostering a deep emotional bond. Faye affectionately addresses her as "Onee-sama" (Big Sister) despite their differing social positions.

She possesses lilac hair and wears a modified maid uniform distinct from other household staff; a traditional apron modifies the otherwise revealing outfit, reflecting her status as the youngest maid and Faye's favored confidante. Sofia exhibits a reserved, introverted personality, characterized as a Shrinking Violet who remains quiet and withdrawn except with Faye or John. Her loyalty to Faye manifests as profound, unquestioning devotion and eagerness to fulfill any request.

This dedication is tested when Faye departs for schooling, entrusting John’s well-being to Sofia. Interpreting Faye’s directive literally, Sofia engages in a sexual relationship with John during Faye’s absence, though her emotional attachment remains stronger toward Faye. Upon Faye’s return, Sofia participates in a consensual polyamorous relationship involving Faye, John, and herself, including explicit encounters with all three. Sofia’s primary romantic and emotional focus consistently centers on Faye.

Her narrative concludes tragically when Faye is compelled to enter Lord Mark’s custody to resolve the family’s financial ruin orchestrated by him. Accompanied by Sofia to his mansion, they encounter an ominous gathering resembling an impending orgy. In the final scene, Lord Mark rapes Sofia off-screen, emphasizing his predatory nature through her visible distress and horrified reaction. Plans for a sequel episode included further non-consensual scenarios involving Sofia during the orgy and a potential rescue by John, though this continuation was not produced due to budgetary constraints.