Mizuki is an anthropomorphic antelope with brown and white fur and backward curving horns. She wears a white tank top with blue hearts and a gold sash. She also wears a red and white polka-dotted skirt and blue and white polka-dotted stockings. For accessories, Mizuki wears a red necklace, gold, red, and blue bracelets on each arm, and a gold star-shaped ring on her right horn.
Mizuki is quite energetic. As Buster Moon's new intern, she becomes flustered when he needs her to distract his audience, but is able to think on her feet, such as when she decides to host a VIP tour. She is also cheerful and friendly in her interactions with the performers; in particular, she idolizes Ash.
Mizuki films Buster's introduction to the audience for Sing on Tour, but when a circuit board blows a fuse, he tells her to distract them while he helps Miss Crawly. Mizuki then leads the audience on a backstage tour, introducing them to all the performers. She eventually reunites with Buster when the circuit board is fixed, and films him as he tells everyone to enjoy the show.
"We're live! The audience can see you!"
— Mizuki to Rosita while she's practicing her routine.
"Okay, so, our next star is my personal hero. I've actually been wanting to meet her for a long time!"
— Mizuki while approaching Ash's room
"Ah, let me take a little looksie!"
— Mizuki to Johnny, before she fixes his piano device.