Arbok

Arbok was a wesen hit man, and Königschlange, an incredibly dangerous and unpleasant cobra like creature, who was Hired by a royal called Mia, to cause and confirm the death of Monroe, he was the seeming main villain of the Episode "Over My Dead Body"

History
He hired to Skalengeck to help him, however a female Blutbad called Angelina Lasser killed one of them, the one who was meant to kill Monroe. So Arbok and his assistant kidnapped her. Upon finding she was facing a Königschlange, this terrified Angelina, who new that Königschlange were much more dangerous wesen. Coldly he molested her, while telling her, she was going to have to assassinate Monroe now, or he would kill her. What he didn't know, was Angelina was a old girlfriend of Monroe's, and so she betrayed Arbok, and went to Nick.

When Angelina delivered the seemingly dead body of Monroe, Arbok identified him as dead, unaware they were using a special potion, that brought him so close to death, that even Arbok's enhanced senses couldn't tell the difference. Thinking it was done, he called Mia in, to get paid. But as Monroe was quickly approaching real death, Angelina broke character and gave him the antidote. At that moment Nick and Hank attacked, confused Arbok ran, Nick ran after him. Recovering his senses, Arbok ambushed Nick, and the two thought, and Arbok's cobra like reflexes proved to be to much, even for Nick's Grimm powers. He Knocked him down and drew his gun ready to shoot him, when Hank caught up, and blasted Arbok with one blast from his shotgun, killing him instantly.