By getting the Dragonborn DLC you open up a new quest that may be the hardest battle you have ever fought. If you have ever played the game on anything over Adept, you will understand what a hard battle really means.
Fighting Alduin and the first Dragonborn may have prepared you for The Ebony Warrior, but even at level 80, this may be a challenge for the most accomplished Skyrim players.
The Ebony Warrior will appear at any given location on the map when you reach level 80 and have purchased the Dragonborn DLC. He will offer you a duel to the death and await you at Last Vigil, in the depths of the Rift.
It is unknown who The Ebony Warrior is at first glance, due to his face being covered by the Ebony armour he is wearing. He tempts you in by saying he wants to go to Sovnguard after a mighty battle.
Not only does The Ebony Warrior gain the perks that you can gain if you use the heavy armour branch in your skills, but he has a clever grasp of magic, an enchanted sword and bow and even two shouts.
As you know, Nords and some other folk can learn shouting from intense work with the Greybeards, even though only a few are allowed into their summons. We suspect that The Ebony Warrior had counsel with them, or possibly learnt the shouts on his own, which is a very hard thing to do. He can shout Unrelenting Force and Disarm, like most powerful Draugr.
This is only a small quest and one many will find easy if they play on simple difficulty. But if you are playing on Adept or higher, be prepared for a tough fight with a formidable enemy.
The Ebony Warrior isn’t a DLC and you can play it as soon as you have Dragonborn and are at level 80. Like Vampires appearing in towns when you buy Dawnguard, The Ebony Warrior will appear whenever you happen to be.