Board Thread:General Discussion/@comment-24382631-20140110234616/@comment-31121580-20180629224622

Shinigami Source of power is Spirit Energy, Butterfly Aizen is a Transcendent being meaning his reaitsu is magnitudes higher than yamamoto so yamamoto bankai regardless of heat would not affect aizen, since yamamoto bankai is powered by yamamoto own reaitsu which is highly inferior to Transcendent level characters like ichigo and Yhwach as seen with Yhwach 1 shotting Ichibei after awakening his true power.

Yamamoto Could take on Aizen First form and 2nd form as he is still a shinigami once he breaks into Butterfly form he is no longer a shinigami but a creature in a higher dimension.

this is the system of cultivation Kubo had started from the start, those with higher level reitsu= higher stats and higher power in every area including speed, durability, strength, if Aizen as atranscendent has higher reaitsu than yamamoto it means all of his stats and power is vastly superior to yamamoto regardless of shikai or bankai

EOS aizen is vastly superior to Yamamoto enough that even his mere presence can erase yamamoto.

abilities are 2nd to reaitsu/Spirit Power which is the source that powers thus said abilities, the one with higher = advantage those much higher= can easily 1 hand and even use 1 finger to stop their attacks, and those massively higher can easily crush them via Presence/Reaitsu crush like Aizen did to bankai Ichigo and Grimmjow