Chibiusa Tsukino is the Crown Princess of the thirtieth century utopia Crystal Tokyo, and is the civilian identity of Sailor Chibi Moon. This is the second animated depiction of the original manga character.
Chibiusa retains the same appearance as she does in the original manga.
Chibiusa first appears in Conclusion and Commencement: Petite Etrangere. She falls from the sky through a time portal and lands on top of Usagi's head, and kisses Mamoru in the process. She introduces herself as "Usagi Tsukino" and asks Usagi why she has the same hairstyle and the same name as her. Realizing that she's found the person she's looking for, Chibiusa pulls out a gun and threatens Usagi to give her the Silver Crystal quickly.
She later uses the mysterious magic of Luna-P to bewitch Usagi's Earth family in accepting her as their relative. She is seen carrying a silver key and another Silver Crystal around her neck.
In Act 16-Abduction, Sailor Mercury, when Sailor Moon attempts to interrogate Chibiusa she runs away, scared. She ends up at a park. At this point it's begun raining so Chibiusa shelters under the slide. She is found by Mamoru later, who brings her back to his apartment. When she wakes up, she shows him Luna P and explains that "Small Lady" is her nickname. When asked about the Time Key, Chibiusa says that she needs the key so she can go home. She then asked Mamoru if Sailor Moon was indeed strong as they said she was.
In the seventeenth episode, she had followed Usagi to the arcade where she easily beat the enemy on the Sailor V video game in seconds. When she saw Usagi's parents together, she recalled how her own mother and father loved one another very much and seemed to have forgotten all about her as well. Hurt and lonely, she had run off to the park where it started to rain.She uses Luna P to manifest an umbrella.
In Act 18-Invasion, Sailor Venus, Chibiusa is playing with her new friend, Momoko Momohara, when Usagi and the others return from the battle. Seeing the Black Moon earring Mamoru was holding, Chibiusa freaked out by its presence. Later on, she had stolen Usagi's Crystal Star brooch and attempted to return home to the future. After the battle between Sailor Venus and Calaveras, she begged that Sailor Moon help her save the thirtieth century as soon as possible.
At the beginning of Act 19-Time Warp, Sailor Pluto, Chibiusa, who has just revealed she's from the thirtieth century, asks Mamoru is she can stay with him the night. Mamoru takes her and Usagi back to his apartment where Chibiusa falls asleep. The next morning, she uses her Space-Time Key to take Sailor Moon, Sailor Venus and Tuxedo Mask to Crystal Tokyo. They meet Sailor Pluto, who is about to attack them for breaking the final taboo but Chibiusa intervenes, explaining that she brought them with her to save her homeland. She then reveals that she's a Princess. Sailor Pluto grants the group access to the thirtieth century. When they arrive in Crystal Tokyo, they are immediately attacked by Esmeraude and the Boule Brothers. After defeating them, Chibiusa takes them too the Crystal Palace, where they encounter Diana and her own father, King Endymion.
In Act 20 - Crystal Tokyo, King Endymion, Chibiusa is revealed to be the future daughter of Usagi and Mamoru, and is in fact 900 years old; despite her youthful, child-like appearance.
In Act 21 - Complication, Nemesis, Chibiusa feels very guilty for Sailor Moon's sudden abduction, as she had stolen the future Silver Crystal to prove to a bunch of children that she was really the Queens daughter and was indeed capable of great strength and power. Due to her taking the Silver Crystal from its rightful place, Crystal Tokyo became defenseless and more vulnerable to the Black Moon's violent attack. When alone, she is approached by Wiseman himself; who persuades the young princess that he is the only one who can truly understand her. Intrigued and gradually falling under his dark power, she goes with him, as a black crescent moon mark appears on her forehead.
In "Showdown: Death Phantom," upon seeing the near lifeless form of Sailor Pluto before her very eyes, Chibiusa finally broke free of the evil energy controlling her and expelled Black Lady from her mind and body. The Silver Crystal of the future came before her and enveloped her in its pure light of positive energy, transforming her into the standard Sailor form of Sailor Chibi Moon.