Sailor Neptune was the eighth Sailor Senshi, aka Sailor Scout, introduced in the series. Unlike the original Inner Senshi, she was not awakened by the moon cats, Luna and Artemis in 20th-Century Tokyo, but rather awoke on her own. Her civilian identity was Michiru Kaiou, or Michelle in the dub.
She was introduced in the Sailor Moon S season of the anime and Infinity arc of the manga. Sailor Neptune fought alongside her partner and lover Sailor Uranus in defending the Solar System from outside threats. In both versions of the story, she was elegant, sophisticated, capable of sharp anger, and sometimes cold, whether she was in civilian or Senshi form. She was fully dedicated to her duty as a Senshi. Her powers were based on the sea or ocean (not just water in general like Sailor Mercury).