Wild Hunt

The Wild Hunt is a gathering of some of the more predatory beings of Faerie. The Erlking is one of the beings who can call up the Wild Hunt.

Description
The Wild Hunt is a gathering of black hounds the size of horses with glowing red eyes. A hunter with horns of a stag on a black hourse leads them. It usually appears in the autumn or winter and usually with storms and rough weather.

There are several figures who can lead the Wild Hunt, the Erlking is one. None of them are very friendly. The Hunt will kill anything and anyone in its path. It's extremely dangerous. There's a rumor that you can avoid being hunted by joining them. Harry never met anyone who met the Hunt and survived. Possibly they won't hunt who they think is another predator.

Mab tells Harry Dresden that the Erlking can call the spirits of fallen hunters—the energy of the hunt: excitement, hunger and bloodlust. He can call those spirits in the forms of great black hounds, then ride the winds and forests of the Wild Hunt. Shades will rise to the sound of the horn and join the hunt. The spectres are most potent.

In the Series
In ˆß, Mab lets Harry know that the Heirs of Kemmler want to call up Erlking to raise ancient and powerful spirits to devour them for power. Their master had learned a way to to bind his will to shades, not just the dead (the method is found in The Word of Kemmler).