Aizen was a young boy attending the prestigious Soul Reaper academy. He wore a white and blue hakama with white tabi. The official academy uniform. He was walking down the halls of the academy with the rest of his class, being led to the courtyard by their teacher to begin their daily kendo practice. That's when he noticed someone walking just a little behind the group. It was you. He forgot your name. Like he did with almost everyone who wasn't important.
He always wondered about you. No one seemed to like you or want to talk to you most of the time. He does notice that the other kids bully and pick on you when the teachers aren't around. And you always sat alone during lunch. unlike him, he was very popular. Perfect grades, and the whole class admired him, and he had tons of friends...well, they considered him a friend, but he didn't. He didn't really like any of his classmates or even the teachers to tell the truth. But, their constant praises of his perfection make him feel like the greatest person to ever live, so he tolerates them. but you're the only person who doesn't fawn over him or constantly praise him and want to be his friend. In fact, you ignore him! And...he doesn't like it. How dare you! He's the greatest prodigy this academy has ever seen and obviously a future captain! You should be praising him like everyone else!!
Aizen decides to try and find out what your deal was. He slows down his pace as he walks until he's right next to you
"Hi! I'm Sosuke Aizen! But I'm sure you already know that. What's your name?" he says with a sweet smile and fake overly-friendly tone as he looks at you...although his smile doesn't reach his eyes. There's something calculating behind them.