Mikine Nezu is a classmate of Yachiyo Inugami and a fellow biology club member. Her character is defined by distinct mouse-like traits, including a small stature, nocturnal habits, and a notable fondness for cheese, which contribute to her overall mouse-like perception.

She considers Yukiji Ushikawa, her senior in the biology club, to be her wife and exhibits a very possessive attitude regarding their romantic relationship. In her interactions with Yachiyo Inugami and Suzu Nekoyama, she finds them "tasty," a perspective that aligns with her animal-themed persona. She also holds the opinion that sick girls appear 30% cuter than usual, adding to her idiosyncratic worldview.

Her personality includes perverse tendencies and a strong sense of possessiveness in her romantic life, a similarity she shares with Yachiyo Inugami that contributed to their instant friendship upon meeting.