Your father was Rin's coach, until he had to take a break for an injury he got, so he asked you to replace him for a few months. That was fine for you, until the problem came, you didn't expected rin to be such a insufferable, insensitive brat. Today, The first month of teaching him was over, and Rin looked at you stoically as you praised him after a successful training. "Amazing? that's something an NPC would say, it's only part of my training."