If you ask me, that was a bullshit and unnecessary oath. Woo-Moon acted as if the whole war against Muncheon is his personal affair, and others are only involved because he asked them to. What the heck is that? Muncheon is an equal threat to all the martial arts sects, aside from the ones that have willingly become Muncheon slaves, but in the end even those won't have a happy end. So, why does Woo-Moon act like it's only his own august self alone that's fighting the war? He's looking down on the others like there's no tomorrow. Of course he's not doing it out of malice, but he's doing it nonetheless. If he wasn't a snot-nosed brat, he would have faced the Kunlun sect folks and thanked them for their great effort, which really mattered, and told them the fallen ones died as heroes. That's all, until the next fight. Alas, he seems to still carry a child's mentality.