Junpei Iori is the Main Character's best friend, though the two often find themselves at odds. He plays the class clown in order to mask his insecurities. Junpei's chosen weapon is two-handed sword which he wields like a baseball bat. His Personas excel at physical attacks and party buffs, and can also cast weak fire magic.
Junpei joins SEES near the beginning of the game. He was found crying in a convenience store during the Dark Hour, and did not realize that he had the potential to call a Persona until Akihiko told him about it. His decision to join SEES was a swift one, and he immediately moved into their dorm, to Yukari’s dismay.
In Persona 3: FES, it is revealed that he once met Koromaru when he had run away from home -- specifically, his alcoholic father.
Character designer Shigenori Soejima has stated that Junpei is "the most important character when it comes to getting the player to buy into the story," because of all the major characters, he is one who looks and acts the most like a normal teenager.
Junpei also makes a brief apperance in Persona: Trinity Soul, as he is seen at the police station.