This page by Hecate
Sailor Cosmos is a much debated persona. Some say that she is the final appearance of Sailor Moon. In the Japanese manga this is fact, but, according to volume 18 of the manga, this is not true. If she is anyone, Sailor Cosmos is the final incarnation of Chibichibi. She is the antithesis of Sailor Galaxia. While that evil Sailor represents the ultimate Chaos, Sailor Cosmos represents the ultimate Good and Order. It is with her help that Sailor Moon is able to revive everyone and at last give them their happy ending. Sailor Cosmos is all that is good in the world, with a little bit of hope thrown in.
She is not, however, the final stage of power. She is merely a catalist for Sailor Moon. She may be the representation of good, but it is Sailor Moon herself who is the power behind her. When it all comes down to it, Sailor Moon saves the world all on her own. Sailor Cosmos is the means to Sailor Moon's ends.
How's that for philosophical? ^_~
Mene's Opinion First of all I love her costume! Isn't it just the coolest? Anyway everthing truly important has been said about dear old chibichibi(I do think she is the grown up embodiment of her). 
it all I sort of feel like it was all her fault that the whole mess with the negaverse got started. If she had been stronger and cut off the evil at its root then the poor sailor senshi wouldn't have had to go through so much. *sigh*
