Short Summary: The Dragonborn is bored with Skyrim so has come to Tamriel.
Disclaimer: I do not own anything except my Dragonborn and my Cousland.
It has been a year since the Dovahkiin had defeated Alduin the World Eater and only 3 months since he prevented his former vampire leader Lord Harkon from unleashing the wrath of all of Tamriel upon his clan and saved his friend Serana from becoming a casualty in Harkon's crazy scheme to block out the sun using Serana's blood (of course he tried it afterward and found that the effect only lasted a few hours for which he was grateful) and it had only been a month since he stopped the return of the First Dragonborn Miirak who was planning something on the secluded island of Solstheim.
Now the Dovahkiin had grown bored with Tamriel and decided to set his sights on the distant shores of Thedas as he had heard that there were strong enemies there mainly Dragons more powerful than a Legendary class dragon and apparently there were remnants of the dragon cult still operating there and he was determined to shut them down as the had caused him enough grief.
So he called on his constant travelling companion Serana, strapped on his Dragonbone Plate Armour and strapped on his enchanted Dragonbone Greatsword, Thunder Dragon (don't ask), and the made their way to Windhelm where he bought a ship, hired a crew of some of Skyrim's finest and able bodied seamen who were shocked to hear that the Dragonborn (Dovahkiin in Joor tongue) was leaving Skyrim and they then set sail along the coast past Morrowind and made their way to Thedas.
He heard that in Thedas only four races existed, the Humans apparently as arrogant as the ones in Skyrim, The elves forced into slavery and servitude by the humans, the Dwarves which caught him off guard until he saw that they were not elves but miniature versions of the humans who made slaves of their own kind and the Qunari which was as much the original race as the rest that followed their religion of purpose the Qun.
Thedas has no idea what's about to hit it!
