The Dawnguard are known as a group of vampire hunters based out of Fort Dawnguard in the Rift. In the Second Era, the Jarl of Riften formed the Dawnguard and had Fort Dawnguard built in order to house and monitor his son, who had contracted vampirism. The group expanded upon this mandate and became vampire hunters who traversed all of Skyrim to ferret out their enemy. Eventually, they became victims of their success: the group was disbanded, and their fort was left abandoned, once the populace no longer feared the vampire threat. It is said that they eventually had to kill the Jarl's son, leading the Jarl to banish them from the hold. One legend claims that the Dawnguard were awed by the power of the Jarl's son and eventually decided to become vampires themselves. They preyed on the Rift until someone put a stop to them. In the Fourth Era, the Dawnguard was reformed amid rumors of an increase in vampire activity in order to hunt them down and thwart their nefarious plans.