Before becoming Aria's Amica, Akari worshiped Aria and aspired to be a great Butei like her. Despite the difference in their skill level, she had high hopes in becoming her Amica and gleefully accepted her challenge for it. When their challenge was interrupted by a group of terrorists assaulting a Butei school bus, Akari pushed Aria out of the way of a moving car and took the brunt of it for her.
After formally becoming her Amica, she proved to be extremely loyal and eager to learn under her. She gladly stitches the parachutes Aria uses in missions, often completing it in record time.
A close friend part of the circle Akari and Shino are in. They have a playful relationship, demonstrated when Raika flips Akari's skirt upwards to put her gun back into its holster. Akari has helped Raika and Kirin's relationship progress. Though not as protective as Shino, Raika has proven her loyal friendship through helping Akari save her little sister in mission "AA", a life-risking task.
They first met prior to the start of the series Akari was getting leaf pies. Despite there being only one pie left, Shino allowed Akari to have the last and she would instead split it between them. After that day, Akari became Shino's first friend.
Akari seems to be unaware of how obsessive Shino is, often times not noticing or understanding what she means when she talks about them being together. When Shino outright attacked her when she visited her mansion due to how obsessive she had gotten, Akari quickly forgave her once she had been defeated.
Initially, Akari was very suspicious of Kinji due to the fact he was the only person at Butei High that Aria actively took interest in and sought out. However, she also fears and respects him to some degree due to how in his freshman year he had defeated an instructor during the entrance exams and achieved an S-Rank in Assault. Though their interactions are few and far between, Akari gets defensive of Aria whenever he appears. However, she has shown to work with Kinji when Aria went berserk as shown in Volume 12.
On a practical exam, Urara had looked down and taunted Akari for being so weak. However, later during the quartet battle where Akari's team was against Urara's, Akari outsmarted and beat Urara. In the anime, Kyou would sabotage the surrounding work complex causing it to collapse on them. Despite Urara's rudeness to Akari prior the test, Akari stayed behind to help save Urara. After that event, Urara grew an obsession similar to that of Shino's with Akari. She is willing to do many things for Akari and has perverted fantasies of dominating Akari.
Akari worked with Kaname during Volume 11 in a plot to keep Kinji and Aria separated from each other.
Nonoka is Akari younger sister who she loves very much and goes out of her way to defeat Kyouchikytou and retrieve an antidote to the poison Nonoka was infected with during the Mamiya Family massacre.