Mika, also known as Usagi no Mika, serves as a guardian angel in Angel Tales. She reincarnated from Gorō Mutsumi's pet rabbit, originally named Mikazuki after the crescent moon visible when he received her. This rabbit died alone during Gorō's absence while he cared for his grandmother, succumbing to loneliness before his return. She was buried beneath a crescent moon mirroring their first meeting night.

As a senior-rank guardian angel in human form, Mika's appearance reflects her past: her hairstyle mimics rabbit ears, and orange is her signature color. She adopts a "sexy style," leveraging fashionable outfits and mirror admiration to draw attention, particularly from Gorō. Aged 17 in the first season and 18 in the second, she was born September 15 under Virgo and stands 155 cm (5'1"), with physical measurements shifting between seasons.

Her personality is extroverted, hyperactive, and attention-seeking—traits rooted in autophobia stemming from her solitary death. This fear drives impulsiveness, talkativeness, and clinginess, especially toward Gorō. She openly pursues him with intense romantic fantasies, despite his disinterest, and clashes assertively with Ayumi (reincarnated turtle) and Akane (reincarnated fox), echoing historical animal rivalries; Ayumi frequently reprimands her over-the-top behavior.

Though often self-focused, Mika displays protective instincts in crises, particularly toward children. She aids fellow angels, like helping Nana reunite with Gorō, sometimes seeking validation. Her development involves continuous efforts to conquer loneliness through connection, though core traits—her relentless pursuit of Gorō and attention-seeking—endure.