In Muv-Luv Extra, Ayamine is portrayed as a delinquent who is fairly quiet and usually keeps to herself for the most part. She likes to use brief and blunt remarks to mess with people and deflect conversation and tension. She has a particular dislike for Chizuru and seems to enjoy setting her off. She is a free spirit and somewhat selfish, always looking out for herself. She likes to skip class and hang out on the school rooftop. She has a strong obsession for yakisoba.
In Muv-Luv Unlimited and Alternative, Ayamine is part of squad 207 along with Shirogane Takeru and the others. She excels at close-range combat, making her well suited to the Storm Vanguard position.
She and Chizuru have a hard time getting along (Chizuru is a very severe and stubborn person while Ayamine tends to deflect serious comments with jokes and handle things her own way), which is the cause of much conflict among the team.
Her father (who was a famous army general) was forced into a lose-lose situation in which he abandoned his own comrades to protect fleeing citizens. He was accused of fleeing under enemy fire and dishonorably discharged. This is the main source of Ayamine's dislike for Chizuru as a leader, because she believes that serving under an incompetent leader leads to only two options: fleeing or being annihilated.
However, after experiencing many significant events throughout Alternative, Ayamine begins to open up to her team more and trust them with her life. This causes her to develop a better friendship with Chizuru, as well as the rest of them.