Kyubey belongs to the Incubators, an emotionless alien race combating universal entropy by harvesting emotional energy. This harvest occurs through contracts with young girls, transforming them into magical girls who fight witches. The process extracts the girl's soul into a Soul Gem, leaving a resilient but soulless body. Kyubey deliberately withholds critical details about this process and the ultimate fate of magical girls, who inevitably become witches upon despair. This cycle generates immense energy to delay the universe's heat death. Its form resembles a small, white, cat-like creature featuring four ears: two standard cat ears and two long, tassel-like appendages tipped with pink fading into red dots. Golden rings encircle the ears, and an egg-shaped red oval adorns its back, serving as a receptacle for Grief Seed fragments. Kyubey's face remains largely immobile; it communicates via telepathy. The body lacks visible organs and emits plush-like sounds when handled. Damaged units are consumed and replaced by identical copies retaining all prior knowledge. Kyubey targets girls experiencing extreme vulnerability, such as life-threatening danger or emotional distress, offering one wish in exchange for becoming a magical girl. It prioritizes efficiency over transparency, justifying omissions as necessary to avoid traumatizing potential contractors. Viewing humans as livestock whose suffering is insignificant against entropy reduction, Kyubey employs utilitarian logic, comparing human concerns about soul extraction to human indifference toward livestock. Despite claiming no malice, it manipulates events to maximize despair, including allowing deaths to pressure Madoka Kaname—a girl with unparalleled magical potential—into contracting. Across multiple timelines, Kyubey pursues Madoka due to her potential to become the immensely powerful witch Kriemhild Gretchen, whose energy could significantly offset entropy. Homura Akemi, aware of the cycle through repeated time loops, actively opposes Kyubey. In one timeline, Kyubey abandons Earth after meeting its energy quota, leaving humanity to face witches alone. Following Madoka's wish erasing all witches across time, reality rewrites: magical girls vanish before becoming witches, and Incubators adapt to harvest less efficient energy from "wraiths." Kyubey retains no memory of the previous system but investigates anomalies Homura reports. In *Rebellion*, Kyubey traps Homura within a barrier to isolate the "Law of Cycles" (Madoka's transcendent form) and restore the witch system. It masquerades as a non-verbal mascot while monitoring the experiment. The plan fails when Homura absorbs part of Madoka's power, rewriting reality again. Kyubey and its race are enslaved to absorb curses in her new world, visibly deteriorated and mentally scarred. In spin-offs, Kyubey's role varies. In *Kazumi Magica*, the Pleiades Saints use a deceased Incubator to create Jubey, a flawed counterpart purifying Soul Gems. They magically erase Kyubey's presence from other magical girls in Asunaro City. In *Wraith Arc*, Kyubey observes Homura's deteriorating memories and retrieves a fragment of her time-manipulation shield, preserving its memories of the pre-Madoka universe. Abilities include telepathy, teleportation, selective invisibility (visible only to magical girls or candidates), wish-granting tied to a girl's potential, Soul Gem creation, grief energy collection, and stimulating Soul Gems to induce physical sensations like pain. The species shares a collective consciousness, and individual units are functionally interchangeable.