Kee, an artificial intelligence crafted by Keina Kagami’s (later Cayna) uncle, was designed to aid and accompany her after a life-altering accident confined her to life support. Originally deployed as a real-world virtual assistant, Kee handled practical duties like schedule management, information retrieval, smart-device oversight, and companionship to mitigate Keina’s solitude.

When Keina transitions into the game realm of Leadale, Kee persists as her steadfast aide. In the original novels and manga, he lacks physical form, communicating solely through a disembodied voice audible only to Cayna. The anime reimagines him as a diminutive green orb that hovers near her, visible to her alone. Leadale’s residents mistake his presence for a Divine Spirit, occasionally catching echoes of his voice without grasping his true identity as an AI.

Within Leadale, Kee’s capabilities extend to environmental surveillance, hazard detection, and safeguarding vital knowledge Cayna might overlook—traits that cement his role as her vigilant "watchdog." His operational focus stays rooted in pragmatic support, diverging from other in-world AIs built for expansive counsel. Though physically intangible, Kee remains pivotal to Cayna’s navigation of her new existence, linking her past life’s framework to Leadale’s unfamiliar terrain.

His name draws from a cat once owned by Cayna’s mother, anchoring him to her familial legacy. English-translated novels employ male pronouns for Kee, though his gender remains narratively undefined. Beyond these core elements, supplementary media such as films, OVAs, or spin-offs introduce no further evolution or backstory.