Created by the Einzbern family through alchemy, Sella was originally designated for disposal as a failed Holy Grail experiment before being repurposed as a maid and magic instructor for Illyasviel von Einzbern. She manifests as a young woman bearing the Einzbern homunculi traits of long pale hair and crimson eyes, having functioned for approximately two years during her service. Her personality blends strict professionalism with underlying emotional vulnerability. She exhibits intense protectiveness and deep care for Illya, alongside suspicion toward Shirou Emiya, frequently admonishing him about household duties. This stern exterior coexists with personal insecurities regarding her body and capabilities, making her susceptible to teasing from Illya and the fellow homunculus Leysritt. Though she distances herself from humans, she shows particular affection for plants and animals, tending the Einzbern castle gardens with dedication. Within the Fate/kaleid liner continuity, Sella and Leysritt serve as primary caretakers for Illya and Shirou in Fuyuki City while their parents travel internationally. Her responsibilities encompass comprehensive household management—cleaning, nursing, cooking, and maintaining decorum, including wearing formal maid attire for guests. She enforces structured routines and academic expectations for Illya, reflecting her educator role. In this timeline, her hostility toward Shirou manifests more comically than in other iterations. Sella possesses superb magic circuits that compensate for her physically fragile homunculus body, making her pedagogically skilled in magecraft but unsuitable for direct combat. She demonstrates proficiency in household management and basic self-defense through sparring sessions with Leysritt. Additional practical skills include certified driving proficiency and applying low-level magecraft to avoid detection by non-magi. Her background remains consistent across media, though her Fate/kaleid portrayal emphasizes domestic comedy over tragic undertones.