Sebas is the eldest butler of the Allbance mansion, recognizable by his gray hair neatly combed back and formal uniform. He has served Dean since childhood and was also close to Claire. Showing profound loyalty and kindness, Sebas regularly visited Riria at night during her neglect, talking to her softly and calling her by her name. He provided affection, sharing stories about her mother, father, and brother to ensure she felt loved. He later orchestrated the assignment of Hanna and managed the household to shield Riria from hostility. Sebas is perceptive, understanding Riria's advanced awareness. He discourages reckless magic use and advises the family on her upbringing. He functions as a wise guardian and peacemaker within the household.
