She also has the unique role in which she carries around a mysterious little incense burner. Hidden inside is Princess Kakyuu. That's why the Starlights follow Chibi-Chibi around throughout the anime episodes; they can smell their princess in the burner. However, Chibi-Chibi is not related to Princess Kakyuu in any way.
In the Manga, Chibi-Chibi appears much like she does in the anime. She turns into Sailor Chibi-Chibi as well, but she can talk and transform by herself, just like a normal Sailor Senshi (only a bit shorter). She's rather mysterious, and it is not until the final battle that we learn her origin. In the Manga, Chibi-Chibi is a disguise donned by the ultimate senshi, Sailor Cosmos. When Eternal Sailor Moon threw herself into Caulderon, the mystical river of birth and rejuvination, in the last battle and sealed Sailor Chaos, there was still a tiny speck of Chaos still left in Calderon. This speck festered and grew to a great enemy in the future, and Sailor Cosmos, dismayed at all the destruction it caused in the future, fled back to the past to make Eternal Sailor Moon destroy Caulderon altogether, thereby illiminating any possible threat. She takes the form of Chibi-Chibi to do so.
But what Eternal Sailor Moon helped Sailor Cosmos realize was that the stream of life represented the birth of new hopes along with the evils, too. And if you believed in that hope, you could always conquer the bad. Sailor Cosmos knew that she could no longer fear that threat with all the love and hope Eternal Sailor Moon gave her, and faced her destiny as the true Sailor Cosmos, with confidence and bravery.