The Dawnguard are a group of vampire hunters living and operating in Fort Dawnguard. You may join them to fight against Lord Harkon and his plot to blot out the sun. The Dawnguard was re-formed by Isran in order to combat the growing vampire menace in Skyrim, and initially only consists of him, Celann, and Durak when you arrive. As time passes (regardless of which faction you join), more people join the Dawnguard. The Dawnguard also keeps two armored huskies as war dogs, three armored trolls (tamed by Gunmar), and partially shelters several refugees who fled there for relief from the vampire scourge. However, the latter are not permitted to enter the fort itself.
 Fort Dawnguard
The Dawnguard's base of operations is the ancient Fort Dawnguard in Dayspring Canyon in the extreme southeast of Skyrim. Built in the Second Era by the Jarl of Riften, the castle served to contain the Jarl's son after he became a vampire. To prevent his son from leaving the castle, the Jarl hired a group of mercenaries known as the Dawnguard, who extended their purpose to root out any vampiric presence in Skyrim. However, the group eventually had to kill their charge, forcing the Jarl to disband them and leave the fort abandoned. At some point in the Fourth Era, Isran, a former Vigilant of Stendarr, rediscovered and repaired the fort and reformed the ancient order.
You may join the Dawnguard by talking to Isran at Fort Dawnguard after the Dawnguard add-on is installed; however, you will be expelled from the guild and unable to rejoin if you join the Volkihar vampires during Bloodline. Furthermore, you will be unable to continue the questline if you become an ordinary vampire, but can resume after you cure your vampirism.
 Primary Quests
The primary Dawnguard quest line consists of twelve quests; multiple radiant quests may also be completed over the course of the quest line. Three achievements (80 points) are unlocked by Dawnguard quests.
 Side Quests
- If you choose to join the Volkihar vampires, all members of the Dawnguard will be hostile to you, even if you finish the questline or decide to become mortal again. However, using a Calm spell, it is possible to engage them in conversation. However, if used on Isran, you will still not be able to join the Dawnguard.