Rabi began existence as a living white rabbit named Shirotabi, cared for by a school pet keeper named Mio. Following Shirotabi's death, Mio performed a black magic ritual to revive him. Though the ritual initially restored the rabbit to life, it placed an unintended curse upon him. Each night, Shirotabi transformed into a killer demon. During these nightly states, the rabbit failed to recognize Mio, causing her significant distress. This cycle continued until other characters convinced Mio that Shirotabi belonged with the dead. Mio then broke the spell, allowing Shirotabi to remain permanently deceased.

In the spin-off "Gakkou no Kaidan SP", Rabi reappears as one of the ghost hosts introducing each segment. These hosts present lighthearted short stories about schoolchildren encountering spirits, with Rabi fulfilling this role alongside other ghosts from the original series.

Rabi also makes a brief cameo appearance in Episode 20 of the main "Ghost Stories" anime series, indicating a minor connection to its primary narrative.