Bleach karin and ichigo's real power

When arrancars are going to kamakura town the soul reapers go to ichigo and start training . When they realize that they failed to Increase their power ichigo will call karin and show then their power
How will the soul reapers react? Will toshiro and rukia be ok with it ? What will happen?
But also ichigo and karin have an unspoken secret that the kept for many years. how will the soul reapers react?

(Ok just to make this clear I'm using ideas from other anime and I don't own bleach or any of them)