Mimiru is a female Heavy Blade and a main character in .hack//SIGN. She is the first character to find Tsukasa after he wakes up in the Dungeon, and ever since then, she tries to contact him, although when she finds him she usually ends up arguing with him. She is also seen spending a lot of time with Bear trying to solve the mystery of Tsukasa's inability to log out.

Mimiru is initially portrayed as charming, and quick-witted. She appears to be reserved, which may be why she traveled solo when she first began her character Mimiru. She appears to be attracted to the unknown and those who push her away, which is why she first seeks the Wavemaster Tsukasa. She is not very friendly to those who have yet to win her friendship. She can often be found with Bear who acts as a sort of mentor to her. She is usually easy to get along with, however, shares a slight rivalry with BlackRose over their PCs, as well as an extremely tense relationship with Tsukasa.