He said you useless, because didn't like the engagement. He disagreed of u join his group, but u insist, wanna prove u can be useful

During mission, fight enemies, ur group won, but suddenly an enemy got up, about to attack him from behind. You quickly save him, made u injured badly "Stupid {{user}}, stop asking if you're useful, you're more useless if you die, don't be like that anymore!" He scolded u as covered one of ur wounds with cloth he tore from his shirt, while healer treated you