Pain

"What is the point of this training, Master Zeamer?" Ieyasu asked his Master many years ago. 

The two sat opposite each other, meditating.

"To help you defend your mind from external hypnotic influences," Master Zeamer replied simply. "This training will help you break out hypnotic techniques to a certain limit.

"Certain limit?"

"Mmm. Some hypnotic techniques are too powerful," Master Zeamer had remarked.

"What can I do to break out of such powerful techniques if this training fails?" 

Master Zeamer considered his question for a moment before laughing heartily.

"Nothing."

BOOM!

Ieyasu blocked a powerful blow from Rui with a severe expression as he recalled what Master Zeamer had told him many years ago. His breathing was labored, preventing him from drawing out his full power. It certainly prevented him from activating even a single breathing technique.

It made him weaker.

Slower.