Chibi Chibi fell from the sky, much like Reene/ChibiUsa did, holding an umbrella. The little darling waltzed into Usagi's home and convinced her parents that she was their third child!
Her manga identity rarely speaks until the last few parts, when her knowledge is needed. And we have to wonder--who is this kid? She seems smarter than Usagi! Of course, we later find that she is a reborn Sailor Cosmos, who, in fear, tried to change her own destiny by causing herself to be reborn and getting Usagi to kill Chaos. Sailor Cosmos, whose destiny it was to fight Sailor Chaos. In Usagi, she saw a way of destroying Chaos forever...But Usagi made her see.
Her anime identity can say nothing but, "Chibi. Chibi Chibi!" or occasionally repeat what others say to her. In the anime, she is part of the Light of Hope, Sailor Galaxia's star seed which she lost. Galaxia sent it to find the Light of Hope to defeat Chaos...yet Chibi Chibi in a way was also the Light of Hope.
Chibi Chibi is just too cute and ridiculous not to like, much like the Japanese ChibiUsa...
