The Archer is a Ranger NPC guard with 480 Health and 70 Armor (+30 vs elemental attacks) as well as a self-heal in the form of Troll Unguent. Due to this fact, the Archer can take a long time to kill one on one for those unsuited against it. Against a prepared foe, however, the Archer will fall quickly. Archers are often located on raised lookouts, near entrances to both teams' guild halls, and in the Lord room. This NPC will snare intruders with Pin Down upon aggro, buying precious time for the defending team.
As a general rule of thumb, they will use Troll Unguent when their Health drops to around 75%.