Ai Momoi is a character from the anime and game series Futakoi, introduced as part of a pair of twin heroines alongside her sister, Mai Momoi. Background information on Ai is limited, but her physical profile includes a height of 163 centimeters, a birthday on January 24, and blood type B. A key distinguishing feature is that she wears glasses, which helps tell her apart from her twin sister. No definitive information is available regarding which of the two is the older sibling.

Specific details about Ai Momoi's personality and her personal motivations are not documented in available sources. Her role within the story varies depending on the adaptation. In the game version known as Futakoi Alternative, she is established as a 26-year-old high school teacher working in the Futakotamagawa area, and she is identified as the younger of the two twins. In this same version, Ai holds a significant place in the protagonist Rentaro's past, being characterized as his first love.

Her primary key relationship is with her twin sister, Mai Momoi, with whom she is always paired. The two sisters are depicted as having lived in the same neighborhood as the main character during their youth. Mai serves as the school nurse, creating a professional dynamic where one twin is a teacher and the other is a nurse at the same institution. No substantial information regarding her character development across the series or any notable abilities she may possess is available.