Abyss Watchers

"The Undead Legion of Farron is a caravan of Undead. Sworn by the wolf's blood to contain the Abyss, the Legion will bury a kingdom at the first sign of exposure. Joyous bunch, really. Gaining admission to the Legion is a matter of some ceremony. Inside their keep, snuffing out the flames of three altars opens the door to the wolf blood. Even accursed Undead want to believe they're special, it seems. I pity the sorry souls."

- Hawkwood the Deserter.

The Abyss Watchers are minor antagonists and the first of the Lords of Cinders fought in the Ashen One's quest through Lorian.

Biography
The Abyss Watchers are a group of undead warriors who took after the inspiration of the Wolf Knight from Anor Londo, Knight Artorias. The main component of the Undead Legion of Farron, they partook in "wolf blood" to combat the Abyss. While meant to be the highest good, they were somewhat radical in nature, as any slight threat of the Abyss would be completely burned to the ground by the Abyss Watchers. When they partook to link the fire, it is unknown if only one or all of them linked it.

But as time went on, the wolf blood dried up and Farron was consumed by a festering wood. Their home grew acrid, and the residents were warped into monsters. With the powers of the Abyss Watchers reduced, the Abyss spread across Lorian. The Abyss Watchers were either driven by anger or corrupted by the darkness' influences. Driven into madness, the warriors clashed at the closest source of the Abyss: each other.

By the time the Ashen One reaches the Abyss Watchers' hideout in the back of Farron Keep, the soldiers had massacred one another, leaving only a single survivor to face against the player. As the battle with the Watcher occurs, two other Watchers are shown to be able to awaken from their fatal injuries in desperation to kill the player or the other Watchers, as shown through their madness with glowing red eyes. Fatally slaying the main Watcher kills off the other Watchers, as in a desperate attempt to keep himself alive, the Watcher absorbs the remaining blood of his fallen brethren to heal himself. Doing so revives him as a Lord of Cinder, restoring his ember ash to ignite his body and sword with fire. After one final clash with the Ashen One, they triumph against the corrupt Abyss Watcher and put him out of his misery.

Trivia

 * The reason the Watchers set up in the Farron Keep is because of how it connects with the Catacombs of Carthus, the resting place of High Lord Wolnir who fell into the Abyss.
 * Hawkwood the Deserter was once an Abyss Watcher who decided to not fulfill his duty of searching for the other Lords of Cinder and instead took residence in Firelink Shrine.
 * The additional Watchers wake up based on a timer and are always the same two.
 * A glitch can occur if an enemy is brought up directly to the fog door, it may attract the red-eyed Watcher and distract him for the entirety of the first phase.
 * The Undead Legion Set becomes available for purchase with the Shrine Handmaid after defeating the Watchers.