The vampire lord's sword is actually pretty impressive if it can block the demon king's sword that Luck is wielding. The demon king's sword cut through a demon commander's sword as if cutting through butter. So, the vampire lord's sword is actually better than a demon commarder's sword. The commander was no minor bugger because that's the one who gave Luck the life leech spell. Only that spell allowed him to compete with the demon king. So, yeah, the vampire lord probably had an exquisite sword.