Ruru is the deuteragonist in the Musaigen no Phantom World anime and light novels.
A friendly Phantom that resembles a small, scantily clad girl. She seems to live with Haruhiko and follows him everywhere.
In the XP4 fics, Ruru is currently a member of the Heroes Coalition. She also attends the Vanguard Academy as a student.
Ruru is a small phantom who takes the appearance of a tanned girl with long, wavy, turquoise hair, tied into a hued light blue braid at the back of her haid using a dark pink hair-tie and has deep red-colored eyes. She is currently wearing a white two piece swimsuit underneath a red short sleeveless vest, a golden chain belt with pinkish cloth on each sides and red shoes.
Ruru has a highly energetic and cheerful personality and is usually seen with a smile on her lips. She can also be somewhat childish and naive, but she isn't shy at all and can come off as a blunt, as she sometimes says things that are flustering, which irritates Haruhiko. Ruru also holds pride over herself and often takes the leadership over Haruhiko when he is "slacking off", much to his annoyance. Ruru seems to be quite popular with the girls in Hosea Academy, since she is often asked to eat lunch with others. Ruru is also a very friendly and straightforward phantom, calling other by their first name despite just meeting them.
- She is an anime-original character, who is based of Rira Tokiwa from the light novels.
- She states that her full name is Rururaruri Rurararirararururirirari Rirararururararururararirari.