Sousuke Aizen

Sōsuke Aizen is one of the central antagonists in the anime/manga Bleach.

He is initially presented as the calm, polite, soft-spoken, and highly intelligent captain of the 5th Division in the Gotei 13. He wears glasses, keeps his hair neatly swept back, and projects an image of gentle wisdom and trustworthiness that makes almost everyone like and respect him.

In reality, Aizen is an extraordinarily powerful, cold, manipulative, and ambitious mastermind who views almost everyone else as beneath him. He is a genius tactician and scientist who orchestrated a massive, decades-long conspiracy to overthrow the Soul King and reshape the world according to his own vision.

His most iconic traits include:

• His Zanpakutō Kyōka Suigetsu, which has the ability to create perfect, complete hypnosis (controlling all five senses of anyone who has seen its release even once)
• His calm, almost perpetually polite way of speaking—even when revealing horrifying plans or betraying people
• His overwhelming spiritual power and combat ability (especially after his later transformations)

Aizen is widely considered one of the most iconic and well-written villains in shonen anime history due to the scale of his schemes, his charisma, and the way he subverts the "kind captain" archetype.