Sailor Neptune is a fictional lead character in the Sailor Moon media franchise. Her alternate identity is Michiru Kaiou , a teenage Japanese schoolgirl and violinist. Michiru is a member of the Sailor Soldiers, female supernatural fighters who protect the Solar System from evil.

Sailor Moon is a Japanese manga series written and illustrated by Naoko Takeuchi. It was originally serialized in Kodansha's shōjo manga magazine Nakayoshi from 1991 to 1997; the 60 individual chapters, along with several side stories, were compiled in 18 volumes. The series follows the adventures of a schoolgirl named Usagi Tsukino as she transforms into the eponymous character to search for a magical artifact, the "Legendary Silver Crystal" . She leads a group of comrades, the Sailor Soldiers, called Sailor Guardians in later editions, as they battle against villains to prevent the theft of the Silver Crystal and the destruction of the Solar System.