I loved Big Hero 6! I was always been curious about how Cass is Hiro and Tadashi's aunt--in "Aunt Cass Goes Out" from the TV-series, it's revealed that Cass never married, and since Disney has confirmed that Hiro and Tadashi are half-Japanese through their father's side while their mother was white, Hiro and Tadashi's mother must've been Cass's sister.