Translation: The first kanji used for her surname, "kai", translates to "sea, ocean". The second kanji used "ou" translates to "king, ruler". Then, the hiragana used to make her give name, "michiru", translates to "to be full, to rise". So, her name would come to the translation of "Rising Sea King".

Rising Sea King would make implications to the mythological figure Neptune. Neptune was the god/ruler of the deep seas which would explain Sailor Neptune's powers over the water, Deep Submerge & Submarine Reflection. It would also explain why she is so good at swimming. Also, Kaiou-sei is the Japanese word for the planet Neptune.