Lusternia/Awesome

Lolly Pringle's final act of the Taint Wars: tackling Emperor Ladantine into the ocean to kill him. Though it doesn't stick, it's a great moment of character development for the shy, retiring Lolly.
Orlachmar holding off Zenos during the Elder Wars.

Defiant in his pain, Orlachmar roared, his anger fueling his attack until his sword was a blazing font of darkness. Zenos finally fled, shrieking off into the smoking sky.

Kalikai's capture of Fain and his Traitors is pretty badass. Up until that point, all we've seen her do is smoke her pipe and get hammered. And all of a sudden...

At the head of the traitors' formation was Morgfyre, his face contorted in rage. He blasted Kalikai with a stream of balefire. Surprise registered briefly upon Kalikai's face before she was engulfed in a white hot sphere that blazed with a furious incandescence, enough to obliterate mountains. When the glow died down, she stood there with her head cocked, still smoking her pipe.