Rei is a princess from an underground kingdom featured in the OVA "La Ronde in my Dream". Imprisoned by antagonists seeking the Fountain of Youth, she is rescued by Momo. Rei is accompanied by a dragon companion named Kajira; this dragon later appears in other franchise media under variations such as "Kadzilla". The English adaptation of the OVA significantly changed Rei's dub name to "Fuzzy the Dragon Boy", altering the character's presentation in localization. Rei's role remains confined to "La Ronde in my Dream", with no canonical developments, background expansions, or recurring narrative roles documented in other installments like the television series, subsequent OVAs ("The Bridge Over Dreams", "The Station of Your Memories"), or the manga "Miracle Dream Minky Momo". While Kajira/Kadzilla is later established as a manifestation formed from collective human grief after Momo’s death in the original series, this lore does not explicitly reconnect to Rei.