The Hunters are a group of rebel Watchers who have come under the dillusion that they must kill all of the immortals in order to protect mankind. They have appeared in a few episodes of Highlander and are quite dangerous to immortals, perhaps even more so than any other....here is why:
1) Hunters are Watchers, which means they have access to the files on all of the immortals: their location, their power, their loved ones, their favorite food, EVERYTHING. They know their prey better than anyone else could.
2) Hunters are mortal. The Quickening will not detect them. They do not care about holy ground. They do not care about fighting with swords, guns work much better. They do not care about fighting one on one, they attack in a group.
3) Hunters can expose the immortals if they so desire, enough said.
Hunters represent perhaps the most danger to immortals if they play their cards correctly, and being as most of them are quite intelligent, most of them do.
The Immortals do have one asset against the Hunters, the other Watchers. The Watchers do know of Hunters, and the Defense Branch seeks them out, and destroys them quickly and efficiently.
Notes:
The Hunters, as Watchers, also know about the Kindred, Garou, Mages, etc. and kill most of them in addition to the Immortals, only Mages have a prayer of being spared, as they can make an excellent addition to the ranks of Hunters.
Strictly Storyteller knowledge coming up.... as it makes an excellent story plot...... do not read further down this page if you are an immortal player character..........
As irony would have it....the leader of the Hunters is an Immortal who has remained undetected by the Watchers. He is quite new, perhaps only "killed" 60 years ago. His plan is to use the Hunters and their paranoia to cut the number of immortals he would possibly have to face down. His directions are to bring the immortals to him, upon whence he will dispose of them in a most thorough manner. None else are allowed to be in the "dungeon" while he sends them to a final death. He himself is becoming quite powerful off of this easy Quickening, he is currently a level 7 Immortal. An ally of his, a 9th generation Brujah, is the only one who knows of his secret. He does not have a permanent base, he moves between four cities throughout the world: New York, London, Moscow, and Hong Kong.