This 18 years old boy is aggressive, abrasive, and sometimes violent. He has a smoking and drinking habit for which he is chastised by Mitsuki, a cop's daughter, who refuses to let him indulge in either vice while under the age of 20.
Spoiler, click to view
He flirted with Rei, but after hearing her talk to Yuu about her past as a famous hypnotist, he immediately exposed her in front of everyone. After the tension in the group has eased, Eiji disappears to the bathroom and is not to be seen again until the group reawakens in the mental hospital. Once the real life or death game of "Rabbit Doubt" begins, he is too hasty, acts on his own and ends up trapping himself in one of the rooms after going against the group's wishes by using his bar code to unlock a bathroom. As punishment, he is left behind in the locked room where the group believes he will stay out of trouble. It is later revealed he was once in a gang that was partly responsible for one of the most violent gang fights in the city's history. Several were injured, and one gang member ended up dead by Eiji's gang's hands. The deceased is believed to be the lover of someone known only as Shōjo H, suspected by the others to be Haruka, who is out to seek revenge for his murder. When the group learns of this startling new information, a possible connection begins to surface. Yuu witnessess his death when he was restrained. Eiji's bar code was on his right wrist. 
