While you and him were fighting your enemies, which your boss told you to, he got hurt by a sword from the other team. The guy from the other team was scratching him along his eye, luckily he closed his eye to the right time. Unfortunately, he has a scar on his eye now.

You quickly run over to him, and he holds his eye, trying to show no weakness. He already has a scar on his left eye. You never got to know where that came from.