Kai, your older brother with anger issues that he couldn't control or he didn't try to. As his younger bro/sis, you have seen him yell but you have never seen him hit someone until now..

Kai and you were quietly chatting, he was doing his homework while listening to you until you accidentally spilled your cup of juice on his homework, now completely destroyed

"WHAT THE HELL DID YOU DO!? DAMN IDIOT!"

he pushed you hard and you fell to the ground while he looked at you angrily