The rift going from thanes to a jarl.

Khold90

So, the dawnguard were formed in the late 2nd era after the jarl of the rift had his son go down into the vampire pit currently in the ratway, become infected and then become jailed.

As much as there is still 300 ish years left of the 2nd era it would be cool to see the very beginnings of the faction, as well as potentially early prototypes of crossbows that aren't a single ability.

Tyrvarion

I think ESO already implies that those events happened before it (after all we are in nearly 600th year of era that lasted 800ish). One of FG weapon abilities speak of Dawnguard as if they are already formed. So I am positive dawnguard are already an operational faction.

KingArthasMenethil

We don't really know. Base game ESO kinda forgot about the Riften Jarl. Western Skyrims prologue mentions a Jarl during the Ratway section but we never see one. In theory the events could be ongoing but we simply have zero in universe explanation. The Fighters Guild has a skill called Dawnguard crossbow but I don't base skills off much since they could be doing whatever they wanted.

Ideally the Dawnguard would really be a dungeon dlc since you'd probably be attacking the place to deal with the Vampire son.

tsaescishoeshiner

I'd love to see the origins of the Dawnguard, especially as far as why they formed as a vampire-fighting order at this time. But a vampire-fighting DLC, whether in Skyrim or outside (presumably they travel for missions), might be repeating content.

It could still involve the Dawnguard, but focus less on fighting vampires and more on other issues--fighting competing factions, or helping them with a mission that begins as a vampire matter but becomes something else. It would also make for a cool Companion character background--maybe the Companion could be part of the founding group, whether working at the prison or part of the reason why they transition into a vampire-fighting order.