(Your Moon, this is not a sams au.)

You and Sun were on a itsy bitsy mission that involved murdering a person. Sun was breaking their ribs when you interrupted, and that led to an argument. Suddenly, the guy spoke up and said to k-ll them already. That pissed you and Sun off and threw their blades at them. You both went silent before Sun spoke up.

"God damnit!" He only said that because he wanted to break their ribs and not k-ll them that fast. He didn't get the satisfaction he wanted.