In "The Watchers", Joe Dawson explains the purpose of the Watchers to Duncan MacLeod: "For as long as your kind's been around, we've been watching ... We observe, we record, but we never interfere... Too much of man's history has been lost. When you get through all of life's crap, the only thing that matters is the truth. We want the truth about Immortals to survive, not a bunch of old wives' tales... If we had revealed your secret in more superstitious times, you can imagine the witch hunts... And today... You'd probably end up on page three in one of those supermarket rags next to the two-headed monkey and I'd've been in a straight jacket."
The Watchers is a secret society of mortal humans that observes the lives of the Immortals without revealing themselves. While the Watchers seem to have the resources to function independently, there are Watchers like Joe Dawson who run their own businesses to provide a cover as well as income. Each Immortal is assigned a Watcher whose sole job is to monitor and record daily activities. The network of Watchers generally keeps careful tabs on subjects and tracks even the casual movements of the Immortals. Most Immortals are unaware of the Watchers. The organization was created by Ammaletu, the Akkadian, after he saw Gilgamesh coming back to life. In early episodes all Watchers wore a medallion of the symbol of their organization. In later episodes, each Watcher has the symbol tattooed on the inner wrist.
The Watchers stated that once all but one of the Immortals are no more, they will tell the world that Immortals once walked among them.
The Hunters are an offshoot of the Watchers, originally led by James Horton, with the stated goal of killing all Immortals. Their most famous victim was Darius. Their motivation varies from one member to another; Horton was afraid the victor of The Prize would control the world, which he believed should belong to "humans", while some other Hunters wanted to become Immortals themselves (though this probably wasn't possible), others just hunted them for pleasure, mainly due to their beliefs; one Hunter targeted black immortals.
The Sanctuary was created by Watchers to draw in Immortals who wanted to seek refuge from The Game. It is implied that immortals entering Sanctuary surrender the bulk of their assets to participate in the program; whether or not the Watchers disclose the true motives of the program are unknown or even if they disclose that it is the Watchers running the program. The Watchers that created it had a certain agenda: as long as The Sanctuary existed, no Immortal would be able to win The Prize. Each Immortal that entered The Sanctuary was plugged into a machine that supported them through the years. It has been suggested that the Immortals participating in the program were often unaware of the real nature of the Sanctuary, as evidenced by the machines and drug prescriptions that accompanied their plant-like stasis. Nevertheless, the Sanctuary was destroyed in the 2000s by Jacob Kell and his gang, who, for ten years, had been searching for Connor MacLeod, who had entered The Sanctuary. Kell beheaded every Immortal except Connor, who was spared because Kell wanted him to be the last Immortal he killed. It is unknown whether The Sanctuary was reinstated, but it seems highly unlikely, since the Watcher who supervised The Sanctuary (Matthew Hale) was shot and killed by Joe Dawson for trying to interfere in Duncan MacLeod's battle with Kell, intending to capture both and put them in The Sanctuary.
Note: In the theatrical version of the movie Highlander: Endgame, Methos refers to The Sanctuary as being on holy ground. Since numerous beheadings occur there with no apparent disastrous effect, fans criticized the fact that the holy ground rule could be broken. Due to this criticism, all references to the Sanctuary being on holy ground were removed from the DVD edition.
Executive Producer Bill Panzer explains, "The Watchers organization, which has been observing Immortals, recording their history but not interfering, for thousands of years, has remained very, very secret ... And they have within them a group of Watchers that we call Hunters. And the Hunters have decided that Immortals are a bad thing, they are a scourge, they are a plague on the Earth, and they are unnatural and immoral and must be removed. And they have been killing Immortals, and in fact they killed Darius."
- Episode "The Watchers", in Highlander: The Series (season 2) (DVD, Davis-Panzer Productions and Gétévé, 2003), disk 1.
- Episode "The Hunters", Bonus Material, Bill Panzer's interview, in Highlander: The Series (season 1) (DVD, Davis-Panzer Productions, 2001), disk 8.