He is also using psychological warfare in business.

My key is a very important character.

Sae acted coldly.

He chanted from the bottom of his heart.

He decided to change his character.

His existence is important to me.

He was abusing his power.

I went to the market accompanied by my mother.

If you rephrase that complex theory in simpler terms, it's just common sense.

He daringly accepted the challenge.