AN: Just a small fic that I wrote for a friend. She wanted dark, angsty and smutty and I think this has delivered. Prepare for more from me. :D

Boundaries

His feet were quiet on the once well polished floors of the UAC facility on Earth. Now the floors were littered with broken glass, fragments of wall mortar and scattered corpses, human and monster alike. He moved forward with cat like grace, his gun ready and raised, watching the world around him through his scope, listening with all his C24 enhanced senses.

A boundary, a step between here…and there. A step into the lighted part of the floor, throwing his shape into stark relief, making him an obvious target to his watcher. A boundary, a step between here…and there. The boundary between love…and hate.

The boundary for that had been crossed for him. The death, the murder, of The Kid, and the subsequent infection of his CO, had made the choice. Once friends, now enemies, once lovers now separated by a mutation so extreme to be irreversible, and a heart black enough that it was impossible to redeem.

"Show yourself." Reaper barked into the shadows, turning, ever turning in the light in the center of the arc chamber. "Let's end this."

"Let's" purred a voice from behind him. Even with his heightened senses Reaper didn't have a chance to whirl around and face his lover, turned monster. He was grabbed and his arms yanked almost clear out of their sockets. As he struggled, knowing his cries would be audible down the hall to Sam, he hoped she would flee, flee and warn the helpless world above of the evil UAC had unleashed.

"Kill me." Reaper gasped, pain burning in his arms, "Kill me, like you killed the Kid, like you killed those civilians. Just fucking do it!"

"No." came the growl from behind him. His arm snapped and he screeched in agony. In a second it healed again and he heard Sarge, or what was left of Sarge chuckle. "You preach of contamination Reaper, but you have the C24 just as I do."

"I'm not a monster, you've mutated." Reaper hissed, dark head arched back. "Kill me, god damn you, you son of a bitch."

"So defiant. I always liked your spirit John." The monster who was once Sarge breathed in his ear. The man shuddered at the warmth and fetidness of that breath. "I can't kill you. I could have done so ten times already, just as you could have killed me. We stall my Grimm Reaper."

A metal bar wound tightly around his wrists and Reaper swore violently. "I hate you, fucking asshole, let me go!"

Sarge moved in front of him and Reaper looked at him in despair. So much was still the same. The eyes weren't an animals yet, they were still that dark fathomless black, his skin still mahogany except at his hands. Those were claws.

Lover. Monster.

A claw raised to cup his bloody but completely healed face, but the eyes, those were soft with the rapport they once shared.

"Once more my Grimm Reaper. Then we will fight to the death." John Grimm hesitated, staring into those familiar eyes and nodded. Triumph gleamed in them and instantly the claws flashed down, shredding his pants and underclothing more effectively than anything Reaper could have done with his hands bound.

Haste, haste, hurry, hurry.

There wasn't time for in depth preparation, being ready, and Sarge had never been one for being too gentle. Reaper screamed as he was pushed into, wondering if Sam could still hear. He hoped she could not, hoped she would never find out the depth of depravity her brother possessed.

They fucked, they rutted, they were animals and in that time where they writhed on the dark bloodstained floor among the dead, John couldn't have told you which one of them was the monster.

As they came Sarge looked into Reapers eyes and he whispered something, a secret that Reaper would never share, never tell. "I loved you my Grimm Reaper, my broken angel of death." And John responded with his own words. "I have passed the boundary from love, to hate." And so they came in a great rushing of passion and bittersweet anguish.

They separated, John to retrieve some clothing from the body of the Kid nearby, Sarge to wind the now discarded metal bar around his wrist.

They faced each other, ready. "No mercy." Reaper whispered.

"Sempre Fi, motherfucker." Sarge growled back.

And they attacked.

~*~

The elevator rose towards earth and a pair of dark eyes watched the night sky come closer. "Almost home." He murmured to Sam, cradled in his arms. She was almost home, but he, he would never be home again.