Ayuki is Tomari's best female friend, who, much like Yasuna, is quiet and reserved, though seems to be more social than Yasuna. Indeed, she serves to act as the voice of reason between the interactions of the other characters. Additionally, Ayuki seems to have an interest in observing the people around her and she enjoys learning about the sciences, though most specifically, biological sciences.

It is suggested indirectly that Ayuki is also interested in Hazumu, and later in the anime, she also seems to be interested in Tomari. However, she says that she prefers not to get involved with the developing love triangle and simply observes from the sidelines.