Michelle or Michiru Kaioh is a famous violinist. She is also Sailor Neptune and belongs to the Outer Senshi. She is devoted to her lover Haruka Tenoh who is also a senshi. Her element is Ocean, and the weapon she wields is called the Deep Aqua Mirror.
Sailor Neptune was one of the protectors of the Moon Kingdom from forces outside of the Solar System, a job all three of the Outer Planet Senshi had. She was also the Princess of her home planet, Neptune. It is uncertain of how she was awakended,but it is debated by fans who was a Sailor Scout first, Michelle or Sailor V. She has an affection for Sailor Uranus as lovers, but in the english dub it was presented as they were cousins, though a "hint" of a loving relationship was there, it was never stated. It is also unknown if they had a relationship going on when they were rulers of their own respected planets.
We see Michelle evolve a lot througout the series, we see that she grows in kindness from the beginning, when she was so centered and focused on her mission, but then, she grew more heart and kindness. We also see that her love for Sailor Uranus grows to become one of the most prominent and expressive in the series.
In the beginning of her appearences, she seems hard and cold towards the Inner Senshi, because she feels they are weak with love and need more of a "backbone." However, she learns that with this love, also comes courage and bravery, and she eventually learns to respect their efforts much much more.