Ii

The Nonsense User, a boy that drastically plays down his abilities, yet inevitably solves any mystery he encounters. Ii is an abnormal person. A "defective product." Unable to express much emotion, he is often seen with a neutral expression; however, Ii is able to express some emotion in some circumstances. At the beginning of his second year in junior high, he joined the ER3 System and went to Houston in America for 5 years and later returns to Japan at the age of 19. Upon return, he begins to attend Rokumeikan University in Kyoto. Ii is "friends" with Tomo Kunagisa, though he refuses to admit he has any and instead calls them acquaintances. Also known as the "mirror image" of Hitoshiki Zerozaki, he is believed to be what Ii would be like if he didn't hold back.

Tomo is helped out by Ii at times, having a friendly relationship overall. The two are similar, being unable to fully express emotions, though Tomo can only truly express happiness. Despite this, she and Ii had an incident a few years back that she never wishes to happen again. The incident is believed to be Ii leaving Tomo for 5 years.