Wendy and her army of the dead.

[Pop Guy]

Wendy may be able to deliver a telltale heart to the constant's disseminated skeletons, so that they reanimate as empty shells in her service. 
The reanimated skeletons are only shadows of the people they once were. They have no intellect and without Wendy to guide them they travel aimlessly. 
They do not eat normal food, but require minimal nourishment in the form of ash, bones, or nightmare fuel. If they are not fed for too long, they eventually expire, leaving behind only ash.
As dead, normal (non-planar) damage sources deal them only 10% damage; de facto they have 90% natural armor.
They are considered abominations, so pigs, rabbits, and cats will attack them on sight. Krampus will also despise them as wicked beings, and will attack them on sight if summoned. 
The skeletons can be equipped with any weapon, and will attack the targets indicated by Wendy.