Princess Usagi Small Lady Serenity, formally known as Chibiusa, hails from 30th-century Crystal Tokyo as the daughter of Neo-Queen Serenity and King Endymion. Her nickname "Chibiusa" merges "chibi" (small) and "Usagi" (rabbit), differentiating her from her mother. Though chronologically exceeding 900 years due to the Silver Crystal's influence, she retains the physical and mental appearance of a child until awakening as a Sailor Guardian. She first journeys to the 20th century seeking Sailor Moon's aid to save her future. Initial suspicion towards her parents' present-day selves, stemming from their contrasting personalities with their future counterparts, fosters an adversarial yet sisterly dynamic with Usagi, characterized by frequent bickering underpinned by mutual care. During the Black Moon arc, Death Phantom's manipulation leads her to temporarily serve as the brainwashed antagonist Black Lady. Sailor Pluto's sacrificial intervention restores her, triggering her awakening as Sailor Chibi Moon and cementing her guardian role. Returning to the past in *Sailor Moon Crystal* Season III for formal training as Sailor Chibi Moon, she befriends Hotaru Tomoe, unaware of Hotaru's link to the antagonistic Death Busters. Her Pink Sugar Compact enables transformations and attacks like "Pink Sugar Heart Attack." She evolves into Super Sailor Chibi Moon using the Holy Grail, uniting powers with Super Sailor Moon to defeat Mistress 9 and Pharaoh 90. Post-battle, Sailor Neptune bestows upon her the Deep Aqua Mirror as a symbol of future guidance. Chibiusa's personality evolves from a socially awkward child—teased in her era for lacking powers—into a compassionate, confident guardian. Initial perfectionism and a desire to "become a real lady" mature into a focus on teamwork and justice. Notable traits include fears of thunderstorms and dentists, fondness for rabbits, pudding, and drawing, plus academic strength in art contrasted by language struggles. Relationships define her growth: her profound bond with Sailor Pluto endures, while her connection to Helios/Pegasus in the Dream arc and friendship with Hotaru underscore her loyalty. A transient childhood crush on her father Mamoru ("Mamo-chan") fades without impacting core relationships. Beyond Season III, Chibiusa appears in *Sailor Moon Eternal* and *Sailor Moon Cosmos*, eventually leading the Sailor Quartet as Eternal Sailor Chibi Moon. Her story concludes with her return to Crystal Tokyo, where Usagi implies her imminent birth in their timeline. Parallel media, such as the *Parallel Sailor Moon* side story, depict non-canonical alternate versions of Chibiusa as a glasses-wearing teenager aspiring to bureaucracy.