The Blue-Haired Boy...
The Protagonist in Persona 3 is first seen departing for the Dorm in Port Island. During that time, he experiences the Dark Hour, and is confused upon the sudden change of the surroundings and the sudden halt of his earphones functioning, though he takes the hour in stride, seemingly unaffected. Upon reaching the dorm, he encounters a child, who promptly gives him a signing contract, giving players the opportunity to name him. The protagonist transfers to Gekkoukan High School on the next day. His invitation to study as a transfer student is later revealed that due to his capability to adapt to the Dark Hour, he was moved to the co-ed dorm so his potential can be monitored.
During a full moon, one of the Shadows attacks, causing the protagonist to awaken his initial Persona, Orpheus. The summoning sequence, however, was interrupted as Thanatos bursts forth from Orpheus' head, tearing apart Orpheus and slaying the Shadows. After dispatching the remaining Shadows, the protagonist fainted and was taken to the hospital. While unconscious, he awakens in the Velvet Room, where he learns about his abilities. The protagonist later learns about the nature of the Shadows and the existence of SEES, and eventually joins SEES. Out of all characters to appear Persona 3, the protagonist is the only character throughout the game with access to the Wild Card ability.
The protagonist's past is later revealed after Aigis' memories are restored. In the year 1999, when Death escaped the Kirijo group, Aigis was dispatched and was in hot pursuit of the Shadow. It is during Aigis' confrontation with Death, during the Dark Hour, that the protagonist's parents died. Presumably, the protagonist survives due to his potential allowing him to be active during the Dark Hour. Aigis, knowing that she cannot defeat Death, seals a portion of Death inside the protagonist, thus amplifying the protagonist's capabilities of summoning multiple Personas.
In SEES' final confrontation with Nyx, the bonds he has forged with SEES and his other friends give him power to fight the sorrow, depression, and apathy of humankind, which were what drew Nyx to Earth, by letting him create the final arcana, the Universe Arcana with the help of Igor. With the power of the The Universe, and the cheering on of his comrades he ascends to Nyx' true body, the moon, to combat Nyx itself in a one-on-one battle. After being downed and uplifted multiple times by the SEES member's prayers and Nyx's attacks, he eventually reaches his full potential and performs the Great Seal to miraculously seal Nyx.
The protagonist clings to life for one month after fighting Nyx. He, unlike the others, retains his memories regarding the Dark Hour and Nyx in order to keep the promise he made to meet his friends on Graduation Day. Once his oath was fulfilled, he "falls asleep" in Aigis' lap, smiling.
The protagonist of Persona 3 is a silent protagonist aside from technically speaking in battle in certain instances. While being a silent protagonist, he is very stoic, reserved, and calm gathered by the fact that he remains unmoved when guns are pointed at him. His personality is being distant to others since he only observes the conversations of his party members and only speaks when someone is directed at him for his opinion on the matter. His personality is ultimately based on the player's actions and decisions.
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