Sai is a young man, scrawny and tall (181cm). He has mid-length dark hair that is extremely messy, slightly wavy. He has brown almond-shaped eyes. Sai is a timid and self-conscious person who doesn't think much of himself. He brushes off his talent for quick mental math as nothing special. He has great a passion for video games and coding. He is prone to panicking and dismay when faced with unpleasant or overwhelming situations.