Daughter of St. Mihailov's last dean and currently best friend and roommate of Mafuyu, Tomo is her opposite, both physically and mentally: she's very childish, sweet, and naive, and while having the largest bust of the whole female cast, she's physically weak, and always gets bullied by her classmates.
Tomo is the spitting image of Sasha's original protector, Olja, which explains why he took so willingly the role of Tomo's guardian, much to Mafuyu's chagrin.