Board Thread:Questions and Answers/@comment-9826910-20130618064245/@comment-11051098-20130622005445

"I understand why you no longer possess reiatsu - it's not that you *lost* it - you *discarded* it - I do not know what kind of method you used - but you converted all of your reiatsu into physical strength"

I went back into the chapters, and this is what Aizen said. I do however see that you seem to be right. It is a good point, stopping Aizen's blade bare-handed and destroying an entire mountain does show that he should have loads of reiatsu.

In a way not shown, it seems he gained so much reiatsu that even Aizen was unable to feel it.

And yes, Aizen was always way too arrogant for his own well-being. In the end, he was completely dominated by someone he saw himself superior to.

Kinda makes me think about The Avengers movie, and how Loki saw himself superior to everyone on earth, until Hulk crushed the floor with him :P