Sakai Seiji is Cassie's father and a Masayuman “diplomat” who was granted asylum in Lower Thalia for reasons unknown. He met Cassie's mother, Shalleah Hyaranon, in the capital city of Cinderhome while she was there helping to bring the harvest to market. He instantly fell in love with her, as beautiful as she was, and returned to Traubin with her to begin a family and to get himself even further out of the sight of the prying eyes that might be looking for him.