Hayden Walker was the main antagonist of the Grimm Episode "Bad Moon Rising" He is a Coyotl (a Coyote like creature) and the leader of his respected pack. Jarold Klamper (another Coyotl) married his sister and quickly took her out of the pack to spare there daughter from there kinds ruthless pack mentality. To preserve his packs honor, he had his niece, Carly kidnapped after her seventeenth birthday (the traditional time for females to be integrated into the pack) with the intentions of raping her to continue the inbreeding.
He along with his pack moved to Portland with the intentions of kidnapping Carly, and sent his sons Todd and Kyle to do so. He introduced himself to her, and kept her imprisoned. Upon getting a tip that Jarold, along with two policemen where coming, he had her hidden in the well. The policemen where Nick and Hank (Hank being a childhood friend of Jarold) intially they managed to keep it hidden, however Hank found there room which was set up for Carly to be raped, and then Nick spotted the rope on the well was shaking. Realizing they were going to find her, Hayden ordered his pack to attack, getting there guns. Nick, Hank and Carly escaped into the barn. However Hayden still had Jarold, and offered to talk.
Thinking they were just to ordinary policemen, he planed to reveal his true form and kill them with his teeth, then his pack would eat them, however following Hank seeing Carly change, Nick had to quickly fill him in on what was really going on. As such Hank was ready for Hayden and knocked him down, seeing Nick Hayden realized he was up against a Grimm, and terrified he surrender.
He was arrested by the police for kidnapping.