SEES is composed of students attending Gekkoukan High School.
The player names and controls the game's protagonist, who leads SEES in its exploration of Tartarus.
In Persona 3 Portable, released on the Play Station Portable in 2009, an option was added to control a female protagonist, voiced by Marina Inoue in the Japanese adaptation, and Laura Bailey in the English adaptation.
Within the simulation elements of Persona 3, the player is able to form Social Links with characters in-game, each represented by one of the Major Arcana and granting various bonuses during Persona fusion, increasing the player's proficiency in battle.
Soejima took longer to design him than any other character, as the game's other characters would be made to complement his design.
Soejima wrote in Art of Persona 3, "Initially, he looked more honest, like an ordinary, handsome young man.
To combat Shadows, each member of SEES is capable of summoning a Persona, a being which is a manifestation of one's psyche.
Persona-users summon their Personas by firing a gun-like object called an Evoker at their head.