Fairy

Fairy is one of four AI "Keys", the others being Jinni, Ghost, and Youkai, though the significance of this role is yet to be revealed. Fairy can analyze Hollow environments at nearly incomparable speeds, able to map out pathways, predict enemy movements, and find rifts or exits. She can also manipulate parts of the environment as long as they are electronic in nature. These abilities make Fairy extremely useful for allied Proxies and Agents. Fairy is first encountered near the end of Business x Strangeness x Justness, when she activates in Phaethon's HDD system. She makes a deal with the chosen sibling, calling them "master" and agreeing to help them under terms which she has yet to fully reveal. Throughout the main story, Fairy assists Phaethon in working with the Cunning Hares, Belobog Heavy Industries, and Victoria Housekeeping, among various other factions. Though her abilities prove invaluable, she also consumes a large amount of energy, forcing Phaethon to increase their workload to keep up with high power costs. As the story evolves, Fairy's personality undergoes slight changes, especially when the siblings support each other each time they are working together for commissions and beginning to insist them to call Fairy their "Legendary Proxy Assistant".