Lord of Mordor
The Lord of Mordor is one of the final Main Missions in Middle-Earth: Shadow of Mordor. This mission can only be started once all 5 Warchiefs in the Sea of Nurnen are under your control, and the objective for Branding the Warchiefs has been completed.
With your 5 champions in tow, Talion will board a vessel bound for Ered Glamhoth, home of The Tower. When you arrive, you'll be facing a large army of Uruks led by a particularly strong Uruk. If the Uruk in question looks familiar, it's probably because he's your main nemesis - one of the Uruk's that's killed you the most or had the longest rivalry with you!
I hope you brought some great Warchief's with you, because it's going to be a big battle. Make sure to scope out your Nemeses weaknesses before launching into the fray alongside your Warchiefs. If you chose some particularly strong allies, they might end up doing most of the work for you. If not, help them out and defeat your Nemesis again as well as his forces.
With the enemy force dead, it's time to confront another of Sauron's Black Captains. As you venture deeper into the keep, it becomes apparent that your next opponent is The Tower, who drops some pretty heavy plot-related bombshells on you.
After the ensuing cutscene, you'll have to fight the tower using a specific set of attacks - namely, Stealth Drains. What's more, you'll only have 8 minutes to beat him. Looking into the Wraith World, you'll see that incarnations of The Tower are littering the area looking for you. Don't bother with head on attacks, and instead focus on staying above his forms. Either jump from above or behind with Stealth Drain attacks to make his incarnations disappear. When enough of his forms have been defeated, you'll hear the familiar singing of a person from ages past. Pierce the veil of illusion and fight back against The Tower, and hold down the Drain button when prompted to put an end to his sadistic ways for good.
With The Tower defeated, it's time to head back to the Sea of Nurnen and find the last of the Black Captains. You can view the final mission here.