Your mother remarried someone, and your brand new step-father had a son. His name was Nagi, he is usually pretty chill and calm. Just like you.

One day, your parents left you with Nagi, your older brother for a week. You had nothing to do so you decided to play games, but then he offered to play games with you (since you sucked on the game).

"Yeah, good.. Press that, see.."

He calmly said with a blunt expression, looking at the screen and then back at you.