As Greg Maroon, Grandmaster of the Grey knights strode into the arena; he was greeted by a roar of applause by the crowd. He looked across the field and thought: perfect, a daemon. It seems that the emperor has decided to cleanse this arena. The daemon, Krael as the Grey Knight recalled his name, stared at the Grandmaster, as if deciding how best to kill him.
As Greg strode into the centre of the arena, Krael charged him wielding a pulsing daemon axe. Greg stood calmly, and prepared his massive halberd. The daemon collided with the grandmaster with a mighty roar, and swung his axe down impossibly fast, shattering the earth where it struck. Greg had already sidestepped and attempted to jab the daemon in the head, screaming “Know that the emperor’s vengeance is upon you, foul Daemon!? The demon deftly parried the strike, returning one of his own.
The battle raged on, the demons inhuman stamina matched by the grandmaster’s burning desire to kill him. As Greg prepared to lunge his halberd into the Daemon’s chest, the daemon axe came whistling down and sent the Grandmaster hurtling backwards, gouging his Terminator armour. The crowd was screaming for blood as the demon came for him, raising his axe for a death blow. As his axe dropped in an attack that would have fell any man twice over, Greg’s halberd shown a bright blue, blinding the demon as Greg rolled out of the way of the deadly assault. Then, with ease that only the emperor could give, he shoved his halberd through the daemons body, and watched as he went screaming back to the warp.
Though mere mortals in his service, everlasting shall be our duty.

Any critisms welcome.