Marshall Yatish. Nothing can stop him from delivering "lickin's." Nothing.
How do you stop an Eldan Annihilator from killing all of Algoroc? Blast it in the face with an Eldan cannon, of course!
As a Dominion player, the Vigilant Trail in Wilderrun. You have essentially passed the 6 tests that determine if you are enough of a virtuous badass to be part of the Empire's most skilled soldiers.
After killing the boss of an area, most of the time the enemy will become neutral to you, wary of your unstoppable badassery. It's particularly amusing with speech-capable foes, like the Darkspur Cartel.
"The Invincible" Commander of the Radiant Legion, Toric "The Radiant Star" Antevian, who is quite possibly the most chill, polite, and kind badass you will ever meet.
While the player goes off to kill Morek "Blackjack" Throg, Judge Kain singlehandedly holds off a never-ending tide of Darkspur Cartel with just a rifle and his deadly accuracy.
After repeatedly saying they will look at adding body types and additional customization options post-launch, the 4/8/14 beta patch notes mention that they have done just that. The devs really are listening.
In Warplots, it's possible to summon dungeon bosses that you've defeated (like Stormtalon) and get them to fight for your faction.