Aigis' initial personality is simply to obey orders, although she is drawn to Makoto and begins breaking into his room at night to be with him. Later, she developed emotions, becoming compassionate and loyal to her friends, though she struggles to fully understand her new emotions. She is also very polite to everybody, always using the suffix '-san' when addressing them. Aigis makes her first appearance in Yakushima, where members of SEES are enjoying their vacation. She appears to be looking out towards the ocean, where Makoto, Junpei, and Akihiko are attracted by her beauty. The trio formulates a plan to flirt with her, only to fail. During Makoto's encounter with her, parts of her memories are restored and Aigis escapes. She is later revealed to be an Anti-Shadow weapon developed by the Kirijo Group (to the dismay of Junpei and Akihiko), and also happens to be the final Anti-Shadow weapon still capable of functioning. Ikutsuki later assigned her to SEES as a member, and she enrolls in Gekkoukan High to act as the Makoto's bodyguard.