Cool fight

Russ was the stronger of the two by a fraction, powering Krakenmaw with the greater heft and momentum, but the Lion had the superior dexterity, angling his parries and thrust to catch Russ off balance. They hacked and drew at one another, circling, feinting, slicing through cloak and pelt, smashing the trophies from their armour.
...
	The two of them careened into the nearest pillar- a column of pure stone a metre thick. The Lion thudded into it, sending cracks rushing out. Russ punched him again, then again, his fist furious and speed-blurred, breaking his brother's fine helmet and denting the angel's wings at its temples. The Lion, reeling, swung his sword clumsily, but the blow was weak and did not bite. Russ grabbed him by the shoulders, and with a cry of rage and exertion, threw him bodily across the hall. The Lion hit the ground hard, toppling onto his back and dragging along the stone flags. Russ turned to pursue him, still weaponless. Krakenmaw had been thrown a long way, and as he made to retrieve it, Alajos moved to bar his way.
...
	Russ swung a heavy punch, missing the Lion's helm by a finger's breadth and driving deep into the wall beyond. The masonry shattered, the block imploding under the pile-driver impact. The Lion went to seize his enemy, to swing round into the wall. The two of them, locked close now, crashed into the rockcrete, sending whole sections sliding over the edge
...
	The Lion thought that this was still some kind of honour-duel. They had pummeled one another to the edge of consciousness, demolished half of the Tyrant's palace in their fury, and still the Lord of Angels was demanding satisfaction.
It was madness.
Russ roared out his laughter, throwing his head back against the streaming walls. He forgot it all- the hunt, the Crusade, the sickness in his Legion's soul, the politics of the fraternity of primarchs, the destiny of the species, and rocked in uncontrolled, puerile glee. So he never saw the blow that ended it all.
He never tensed for it, never put up a warding arm, and never even watched for the Lion limping across to him, pulling his bloodied fist back and launching the punch that would crack open his skull and knock him as cold as the tombs of Caliban.

The Great Wolf