Dai is the Ma-Pet companion to Leila Takashiro, one of three main human protagonists. This small, brown-furred dormouse is often mistaken for a squirrel because of his prominent bushy tail, a mix-up causing him visible frustration. A distinctive red lightning bolt-shaped mark adorns his forehead. He possesses a notably strong appetite, frequently leading to gluttonous behavior.

Hailing from Fairyland, Dai was dispatched alongside fellow Ma-Pets Sei and Ryoku by the Queen. Their mission is to locate three human girls destined to become Princess Idols and grant them magical gems enabling transformation. These gems allow the girls to mature into their idol forms, known collectively as Lilpri, tasked with gathering Happiness Tones from humans to restore the fading Fairyland.

As Leila's primary magical support, Dai actively assists her Lilpri duties. He exhibits a responsible and sometimes exasperated demeanor, largely stemming from Leila's forgetful and clumsy nature, which compels him to frequently remind her of important tasks or information. Their dynamic positions him as a pragmatic counterbalance to her tendencies.

Within Leila's home, Dai resides in a miniature bed inside a partially constructed dollhouse. His personal space includes a hamster wheel, reflecting his adaptation to human domestic life while retaining elements suitable for his small size.

He communicates verbally with Leila, the other Ma-Pets, and likely other Fairyland beings, fulfilling his role as both guide and helper. His existence alongside Leila remains a secret from the human world, a necessary condition for maintaining the girls' magical abilities.