Кайо Мічіру

Introduced in the third story arc, Michiru fights alongside her partner and lover Haruka in defending the Solar System from outside threats. In both versions of the story, she is elegant, sophisticated, capable of sharp anger, and sometimes cold. She is fully dedicated to her duty as a Senshi. Her Senshi alter-ego is Sailor Neptune, one of the "four soldiers of the outer solar system". As Sailor Neptune, her element of influence is the sea(not with water in general as Sailor Mercury's powers are); as with many of the other Senshi, this element is closely associated with her planet, which is named for the Roman sea god, Neptune.

She is one of the Senshi who has natural psychic powers, alerting her when danger is near. She seems to be a character with a very deep understanding of things, sometimes even surpassing the other Outer Senshi due to her unnaturally high psychic endowments. Michiru's wavy aqua hair and turquoise eyes are intended to evoke images of her element.