The Guard is a type of villager added by Witchery. Guards can be found randomly spawned in villages generated by Witchery, in particular by the Guard Tower, Town Keep, and Town Wall structures. They have 40 health, and 500 blood. They are armed in leather armor and bows, and as such, drop random leather armor and bows when slain. Guards act very similarly to Vanilla Minecraft's Iron Golems. They will attack any threats to the village, including players with low reputation, hostile monsters, and players that attack villagers (including when seen sucking blood).
A player that has gotten the maximum amount of village reputation can assign villagers to be Guards by handing them a leather tunic.