Hotaru Tomoe is the civilian identity of Sailor Saturn.
She has short dark purple hair, violet eyes, and translucent white skin.
Hotaru Tomoe is a very sick girl who felt better when her father gave her an amulet to protect her. She has been looked after by Kaolinite since her mother died. She attends Mugen Academy. Hotaru is the fusion of both human and machine.
Act 27 Part 2 - Chibiusa Tsukino first meets Hotaru while she is crying from pain on the steps of Mugan Academy. When Chibiusa asks if she is alright, Hotaru slaps her hand away. Hotaru explains she gets these attacks often but it will soon pass on its own.
Hotaru witness the transformations of Usagi Tsukino, Ami Mizuno, Rei, Makoto Kino, Minako Aino and Chibiusa into their Sailor Guardian counterparts. When the Daimon goes after Hotaru, Sailor Chibi Moon dives her out of the way.
After the fight when she inquires as to who they are, Sailor Chibi Moon explains they are all Sailor Guardians each protected by their Guardian Planets. When Hotaru notices Sailor Chibi Moon's arm in injured, she places her hand on the wound as a power flows though her, she heals the injury.