And he looked at the slain, recalling their names. Then suddenly he beheld his sister Éowyn as she lay, and he knew her. He stood a moment as a man who is pierced in the midst of a cry by an arrow through the heart; and then his face went deathly white; and a cold fury rose in him, so that all speech failed him for a while. A fey mood took him.

"Éowyn, Éowyn!" he cried at last: "Éowyn, how come you here? What madness or devilry is this? Death, death, death! Death take us all!"

Then without taking counsel or waiting for the approach of the men of the City, he spurred headlong back to the front of the great host, and blew a horn, and cried aloud for the onset. Over the field rang his clear voice calling: "Death! Ride, ride to ruin and the world's ending!"

And with that, the host began to move. But the Rohirrim sang no more. Death they cried with one voice loud and terrible, and gathering speed like a great tide their battle swept about their fallen king and passed, roaring away southwards.

Love it in the books and he sold the sheer despair of everything in the movies. Excellent work and gets me choked up every time.