Just below the dragons in their hierarchy were the Dragon Priests, who ruled over the denizens of Skyrim, enacting the commands of the dragon overlords. Thousands of years before the events of Skyrim, dragons ruled the land and subjugated all other beings, which the dragons viewed as inferior. Dragons take most of the spotlight in the main quest and beyond, but their influence and long rule in the history of Skyrim and the rest of Tamriel is felt in many of the game's locales. Bethesda's The Elder Scrolls series has a plentiful amount of lore and history written into its fictional world of Tamriel, much of which comes through in the quests and side content of Skyrim.
