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 the protagonist, Junpei Iori, and Akihiko Sanada are attracted by her beauty. The trio formulates a plan to flirt with her, only to fail after she bluntly tells Junpei and Akihiko "You are not the one." During the protagonist'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 (much to Junpei and Akihiko's dismay), and also happens to be the final Anti-Shadow weapon still capable of functioning. Specifically, she is a 7th Generation Anti-Shadow Suppression Weapon developed by the Kirijo Group.