2. Sosuke Aizen
Main Antagonist of Bleach. He was gifted with great intellect and Zanpakutō that can hypnotize any person and take control of all five senses. I can’t even imagine what his bankai could do
1. Genryusai Yamamoto
He is the undoubtedly the most powerful captain of all time. He remained Head captain for over a thousand years. His Zanpakutō Ryūjin Jakka is the strongest and oldest Zanpakto there is. He might have taken down Sosuke Aizen if Wonderweiss was not made.
I hope you liked my list, this list was based on the facts I discovered.