Okay here's Chapter 1, more advice like Davidcus' will be very useful
I'd like to put a special thanks in for Ultra111, who has helped me A LOT with developing this!
EDIT: Fixed some grammar and added a few more sentences in.
“Gabriel! Come with me!” shouted Xavier over the gunfire. As the two marine’s ran across the destroyed base, they came across many dead marines. They seemed to be the only two unaffected by the Black Rage, and even though these marines were honourable warriors, and good friends of Gabriel and Xavier, the Black Rage was unstoppable until the fight had ended. Xavier and Gabriel opened fire as they ran, downing countless marine’s. The two Astartes slowed to a walk,and wiped the blood from their power armour.The danger of the fighting seemed to be far behind them. They had reached the central control room, one of the most impervious rooms around. Chapter Master Gabriel Seth stood in the centre of the room, shooting marines that were closing in on him. Loth and Harls opened fire on the attacking marine’s as well, ultimately saving Seth’s life. “Xavier? Don’t tell me it got you too!” the chapter master asked from across the room, still covered in blood. “Nay, it seems that us 3 are the only ones to be unaffected by the Rage. Perhaps you could enlighten us on how it all started?”
“Of course I will. It all started when a group of Tyranid xenos attacked the base. It wasn’t a difficult fight, nay; there were only a handful of them. We easily defeated them, and even then the Rage did not trigger. Hours passed, and a shadowy figure walked into this very room, saying that he was from the Imperium command. I checked all of his laurels, and they were all completely correct. He was from the Imperium, and we talked about the chapter’s current affairs, until he all of a sudden declared us excommunicated from the Imperium! I did not understand, and I inquired as to why this had happened. He showed me footage of the both of you, at a crashed Imperial ship, saying that you had both shot the ship down. I, of course, knew that this was treachery, and that just because we’re slightly unstable, the Imperium think they have the right to kill us all off!”
“That’s impossible! Gabriel and I were inspecting the ship! It had crashed before we got there. I suppose he showed you the footage of the Tyranids we discovered?”
“Tyranids? He only had the footage of you two walking up to it, and nothing else!”
“Hmm. Treachery indeed. Please carry on, Brother.”
“That was when it started. He emitted a sound that made the Black Rage take control. I shot him dead on the spot, but it was too late. The fighting had already begun, and I was helpless to stop it. I holed myself up in here and attempted to reach some sort of assistance from the Imperium, but I found nothing. That cursed officer jammed our tele-communications as well! And that’s about the time you got here.”
“That’s a lot to take in Brother, but I have one question.”
“Where is that Imperium wretch?”
The trio walked towards the mangled corpse of the Imperium officer, and Xavier examined it. “You’re right. He is clearly an Imperium officer. Except one tiny detail.”
“Which would be?” replied the chapter master
“This.” And with that, Xavier shot the officer repeatedly, until his chest fell loose. “It’s a drone, sir”
“Not only is it a drone, but it’s one of the highest quality. Created by a Techmarine.”
“Treachery within the Astartes?”
“It would seem to be that, or a Chaos legion captured a Techmarine and forced him to make this.”
“Quite likely. But, may I inquire as to how you knew this was a drone?”
“There was no blood around it.”
“Of course.” Just then, Gabriel Loth shouted.
“Brothers! They’ve breached the doors! We need to get out of here fast!”
“I’d rather die.” The doors blew from their hinges. Smoke filled the room.
“DIE!” screamed a Rage infected marine as he burst through.
“Open fire!” yelled the chapter master as he opened fire with his plasma pistol. The Rage infected marines kept pouring through the doors and each one of them was shot down in seconds. All three of them were soaked in the blood of the marine's. After a few minutes the marines stopped coming through. The Chapter Master walked back to the telecommunications desk, and jabbed a button. “Still jammed! Brother Loth, would you go take a look at our telecommunications antenna?”
“Of course sir” replied the young marine
“I’ll go with you” Xavier added in. The two marines walked away with the chapter master repeating the same sentence over and over again.
“This is getting rough Gabriel. Not only do we have a xenos threat, but we have the Black Rage, and a traitor marine possibility. I’d advise you to stay frosty.” The young marine Gabriel had seen much these past hours, so many honourable marines destroyed by the Black Rage. And yet, it seemed that hope was still there. Gabriel and Xavier climbed up to the antenna, and they instantly knew that they had made a mistake. The antenna was not “jammed”, it was destroyed. The xenos surrounding it were chewing on its mangled parts, screeching horrible sounds. Gabriel and Xavier opened fire, bolter fire spraying into the aliens. The xenos lept at the two marine's, clawing at the armour of them. The Astartes pushed the xenos off, and shot deep into the bodies of the aliens. Their tentacles had been blown from their heads, and most of their four arms shot off in the battle. Once the marine’s had made sure the xenos were dead they moved towards the antenna. “Destroyed, not jammed. Without a Techmarine this is impossible to fix.” Xavier noted.
“Then we may as well take the power core from it, put it to use.”
“I suppose you’re right. You go ahead, I’ll take the core. Make sure the chapter master isn’t dead.”
Gabriel climbed down the walls, and walked towards the control room. It had been quiet for hours now, and this had made Gabriel think that the syndrome had subsided. “Gabriel? Is that you?” asked the chapter master. He looked ragged; blood was seeping from his wounds. “What happened to you sir?”
“They came in droves, Gabriel. Unstoppable, they were. They almost killed me, but I managed to hold them off. But, I fear my death is near. One of them wounded me, and it could be fatal. Go! Go help Xavier!”
Gabriel didn’t argue with his orders. He returned to where Xavier was, and saw him climbing down with the power core in his hand. “Gabriel, it’s good to see you! How is our chapter master?”
“He’s near death. The rage infected marine’s got him, and ripped into him. He’s bleeding badly, and I don’t think he can make it. He told me to go and try and find a way to communicate with the Imperium.”
“But our telecommunications array is down, it’s impossible to communicate!”
“Not if we can rebuild it.”
“How do you mean?”
“Well, seeing as that drone was fairly new, and was clearly crafted by a Techmarine, perhaps we can find the Techmarine and get him to rebuild the array!”
“That doesn’t seem like a half bad idea. Let’s go.” And with that the two marines began their search for a way to survive.