The Psychology of All For One: The Tyranny of Ego and the Addiction to Power
All For One (AFO) is the fundamental antagonist of My Hero Academia and the symbolic opposite of hero society. His psychology is not based on trauma or vengeance, but on malignant narcissism fueled by a power that allows him to absorb the identity of others. AFO is the embodiment of absolute tyranny, where power is the ultimate end, not the means.

1. The Narcissistic Core (Worldview)
AFO's psyche is based on an unwavering conviction of superiority, which positions him as the only being fit to rule the world.
The God Complex (The Original Benefactor)
AFO is the only individual in the manga's history born with a dual Quirk: the ability to steal and grant other Quirks. He initially distributed Quirks to needy people, not out of altruism, but out of boredom and to establish absolute loyalty. He sees himself as an architect, a god who manipulates humanity, whose desires are law.
The Absence of Empathy
AFO lacks the ability to see others as equals or even as people with agency. His relationship with everyone, from his brother to Shigaraki Tomura, is purely transactional. Individuals are tools, vessels of power, or pawns in his game to secure his immortality and dominance.

2. The Addiction to Power (The All For One Quirk)
The All For One Quirk is not just an ability, but an extension of the villain's narcissistic pathology, a physical manifestation of his addiction to control.
The Obsessive Hoarder
The act of stealing a Quirk is the psychological act of absorbing the identity of another person. Every stolen ability validates his superiority and reduces the world's uniqueness, satisfying his need to have everything under his control. The more power he accumulates, the more his delusion of omnipotence is reinforced.

The Fear of Irrelevance
The only challenge to his vision is One For All (OFA), a Quirk that symbolizes collective will and transfer. AFO's obsession with eliminating OFA stems from his deepest fear: being superseded by the collective will. He needs to destroy All Might, not just physically, but as a symbol of the hope he rejects.
3. Legacy and Succession (Shigaraki Tomura)
AFO's relationship with Shigaraki Tomura is not that of mentor-disciple, but that of an engineer building his own replacement vessel.
AFO saw in Shigaraki the perfect mix of potential, trauma, and emotional void. By exploiting Shigaraki's childhood trauma, AFO provided him with a destructive purpose, molding him to be strong enough to wield the All For One Quirk, yet broken enough to remain an extension of AFO's will. He did not seek a successor but an under-control reincarnation.
Conclusion
The psychology of All For One is a case study of how unrestricted power corrupts the mind into an absolutist tyrant. He is a villain who does not seek to change the world for an ideal, but to subjugate it to his ego. His legacy is the imposition of calculated chaos to ensure his eternal control, fundamentally challenging the concept of heroism.