An Ideal Self is a concept that appears in the Persona series. Everyone has a "Shadow Self," the part of themselves they don't want to be. They also have an "ideal self," the person they aspire to be.
Megami Ibunroku PersonaEdit
Maki Sonomura is a frail, bedridden girl who has been sick all of her life and suffers from episodic fits of dementia. When she's not in too much pain, she often paints disturbing still-life pictures, escapes into her "Ideal" world and waits for her friends to come visit her.
Part of Maki accepts, and at the same time rejects, this development. Thus, three manifestations of her psyche actually emerge: Maki, who joins the party, representing her "Ideal" self; and Mai and Aki, two alternate selves that represent her innocence and malevolence, respectively. The "Ideal" Maki is the same age, while Mai and Aki appear to look like Maki back when she was a child. Throughout the game, the Ideal Maki is the one helping the party, while the real Maki is held captive by Takahisa Kandori.
Upon knowing her true origin, the Ideal Maki escapes into her own self-pity and refuses to accept the truth, until the protagonist convinces her to snap out of it, and gets the Green Compact from Maki.
The party also finds a Chaos Mirror Shard from Kandori's mirror and a Broken Compact. The two become a Red Compact, and the party saves the Ideal Maki with the help of Setsuko Sonomura and Mai. Mai tells them that there is one more Compact, held by Maki's true self in the Sea of Souls beneath Alaya Cavern. Upon reaching the bottom of the cavern, the Ideal Maki convinces the Real Maki to give up the Blue Compact, and she asks the party to go as she doesn't want the protagonist to see her as she is now.
Back at the school, the door in the library opens with the three Compacts, and the party enters the Avidya World. They find Pandora, an empty form of Maki who devoured Aki and stole the core of the DEVA System from Kandori while serving him. She plans to use it to create a world of nothingness, but the party defeats her and Ideal Maki convinces her to merge back together. Once Pandora is defeated, Ideal Maki reveals that since she's just a shadow created from the real Maki's heart, she cannot go back to the real world with them. As the rest of the party returns to the real world, Ideal Maki kisses the protagonist and confesses her feelings to him before he returns as well.
Persona 2 Tsumi: Lost MemoriesEdit
Tatsuya, Jun, Lisa and Eikichi's shadow selves objected and tried to convince them that resetting the world was the wrong thing to do, and that they needed to accept reality. They had to kill off their shadow-selves before they could advance to the spirit of Longinus, kill him and reset the world. They were able to defeat their shadow selves and defeat the spirit of Longinus only with the help of their ideal selves.