Dawnguard revolves around an ancient prophecy predicted by an Elder Scroll. Foretelling the eternal obfuscation of the sun, the scroll gave instructions on how to perform a magic ritual with a mythic bow and a special blood sacrifice. A legion of vampires known as Clan Volkihar, lead by Lord Harkon, seek to actuate the prophecy by performing the ritual; the Dawnguard, a faction of crossbow-wielding vampire hunters counters their aims. Skyrim's Dragonborn protagonist chooses whether to join the Dawnguard and prevent Nirn for being plunged in irrevocable night, or assist the vampire coven with realizing their malevolent ambition.
