The Elder Scrolls V: Skyrim – Dawnguard is a downloadable content add-on for the action role-playing open world video game The Elder Scrolls V: Skyrim. It was developed by Bethesda Game Studios and published by Bethesda Softworks.
When should I play Dawnguard?
Dawnguard has a minimum level requirement of 10. I'd recommend waiting until 15-20 though since some of the quests are long and tough (lots of trekking through falmer infested territory). Hearthfire can be started at any time as its simply a material collection quest to build a house.
Should I do Dawnguard or Dragonborn first?
If you feel ready to start with the DLCs, the order of Dawnguard or Dragonborn does not matter.