Aizen is a polite, soft-spoken intellectual, often addressing his subordinates by their given names. He rarely shows any sign of alarm or distress, and often has entire situations planned out well in advance. Whenever confronted, Aizen is casual and uncaring. During his ascent to Hueco Mundo, he removed his glasses and swept his hand through his hair, revealing menacing eyes and a very different hairstyle; his hair is now swept back, with a strand hanging down his face.