"Nice to meet you Penny," Doomguy uttered. "Let me bring you up to speed. That out there," he pointed towards the gaping doors of the transport ship, "is a literal beast. It will eat you up, it will chew you to pieces, digest your carcass and shit you out the other end. That's what it'll do!" He cocked his assault rifle, and checked the sights by peering down them. "When we leave that door, we're going to turn things on their head; we're going to reverse this here situation, by throwing ourselves up the literal beast's ass hole, and come out the other end. It's a basic science, and one that I'm an expert in." 

With no further adieu, the Marine gave Penny a brief nod, and then turned towards the hatch. The sounds of war echoed, reaching out to greet him; men screaming and dying; women cursing in anger and injury. He'd join them soon enough, but the thought did not trouble him in the slightest. His heart beating in rhythm to the chaos, he quickened his pace into a sprint, and leapt from the transport with practised savagery. 

There was indeed chaos all around; a great beast that defied the legions of Hell, swam through the air, laying waste to the frozen ground that had covered the desert basin just a moment before. A knight with flaming attire, a familiar portrait of Hell itself, stood in the background, as troops rushed around him; energised as they were, to beat back the likes of Doomguy.

A demon ran up to him, four limbed and breathing fire; Doomguy darted out of its reach, pasting its skull with hot led. Another such creature came from his side, and he leapt away, blasting its kidneys from its lower abdomen with another flurry of searing rage. Then something not unlike an Angel came for him from above, its gaze terrifying, its being holy and yet unholy - Doomguy's rifle clicked as the magazine ran empty. Throwing the rifle aside, he pulled forth his trusty Super Shotgun, a double barrelled monstrosity. 

As the creature came for him, Doomguy responded in kind, unleashing a dual barrage of devastating slugs that tore the "angel" a new mouth right below its neck. It fluttered to the ground, screaming and crowing. 

And then Doomguy was struck from behind by another demon, its red flesh hot to the touch, but he was able to launch it several feet backwards with a push of his booted feet. It fell onto the sand, roaring in anger, but before it had time to stand, he threw aside his super shot gun and pulled out his plasma rifle; his back a seemingly endless arsenal. 

The beast charged, and Doomguy reduced its face to ash. 

And as the legions of Chaos came forth, rounding on him, he could only hold down the trigger, and keep it there, until they all went away.