May appear as a random boss in a Dungeon.
Though not as easy as the Undead Giant, the Watchers can be taken down fairly quickly if you avoid getting surrounded. Two Watchers wield cleavers, the other a rifle. Your first move should be taking out the rifle-toting one. Once he's down, focus on one of the other Watchers, avoiding their cleaver swings with sidesteps. Take them down one by one, and you should have no problem.