Mao is a baby devil who appears suddenly in the life of Honoka Sawada, a lonely middle school girl. He has short pink hair, black eyes, a tail, and small wings on his head. He typically wears a blue jumpsuit with a yellow bib that bears his name in English. He considers Honoka his mama and is regarded as her child. Like other devil babies in the series, Mao can perform magic based on costumes he wears. For example, when he puts on a dinosaur costume, he is able to breathe fire. His personality is generally cheerful, friendly, and even-tempered, though he can become grouchy or cry easily when upset, such as when he is first left at a daycare for devil children. Despite moments of fear or whining, he is very attached to Honoka and enjoys being with her. He loves pancakes and is playful and curious. At the daycare, he befriends other devil babies named Karin and Rai. He also forms a bond with Shin Sugisaki, who becomes a substitute parental figure alongside Honoka. Mao's arrival gives Honoka a new sense of purpose and companionship, helping her overcome her loneliness. As the story progresses, Mao continues to explore his abilities and his relationship with Honoka deepens, showing growth in their mutual trust and affection. His magical powers activate through costumes and require proper release; if his magic builds up without an outlet, it can cause him to develop a fever.