I think Chibi-Usa's best real friend. She comes from the future in some (I
know I'm farfetched) bizarre way with Pluto's help.. to save Usagi. I know
I'm rusty on this. After that espionage, they become really close friends.
She even refers to Pluto / Setsuna as 'Puu'.
Setsuna even shows that she cares for her, in some episodes. Also, Pluto even
gives Chibi-Usa a Time Key thing sorta, so that she can travel in time.
this is sorta a long story. Yaddayadda. In the SuperS.. Chibi Usa notices Hotaru
fainted on a street.. she wines and calls someone.. and then they become
friends. Woo. I have to research on this one again.