Akari acts rather sweet, and caring towards people around her, yet her true behavior towards other seems rather cold, lack of care, and even a bit sadistic. She uses her happy, innocent behaviour in order to blend in, and remove any suspicions put on her by other humans. Her various likes and dislikes resembles that of Korosensei, which includes a love for sweets, focus on goals, and fixation on breasts. She is rather intelligent, but just 'chooses' to think averagely to lower suspicions. She also has a love for blood, claiming it as a 'tangy drink'
She was one of the hundreds that underwent the Cthulhu Dark Rest, being one of only two to survive, the only other being Itona. Akari found the human race 'strange in a good way', seeing how dynamic the human race was. That didn't mean she had full sympathy for the race, and still agreed to Malamar's plan for the humans and their world (if they don't cooperate with him). She was found by Shokoshu scouts, and she and Itona were nursed back to normal health.
Akari had been tasked by Malamar to go down to earth, and 'blend in', keeping her origins a secret. With that in mind, she went to Yunibāsaru Junior High School, under the identity as a transfer student from the Ishikawa Prefecture, yet didn't bother to change her name, thinking it didn't matter too much to her. Soon after arriving, she runs into Twilight, whom she aqquainted with.
Throughout season one, Akari remained alongside Twilight as a side character, not getting involved too much during her appearances.
While she acts like she's simply average, she is actually very smart in comparison to the students she's with. Her advanced knowledge camen from her hybridization.