Sons of Iron
Background for my space marine chapter
The hive world Aurum was in dire danger and they could see it coming clear as day, a force of heretics had been taking out the outlying worlds in the area and they knew it was only a matter of time before it got to them. They entreated the imperial forces for aid but there was an emergency elsewhere and Aurum was considered a low priority, they were stripped of the meager guard normally posted there for the more pressing campaign. Most of the inhabitants had abandoned hope in the wake of the inevitable wave of the chaos horde.
Some were not prepared to accept that defeat however. A group of techpriests calling itself the Iron fathers launched a heretical conspiracy. They began scavenging equipment and junked parts to construct weapons and begin work on a defense force while examining the hive gangs. They found one that was actually liked by the people in their turf and supposed to be both reasonable and decent, the sons of thunder, who was already preparing for the incoming invasion. The iron fathers approached the sons of thunder with their plan and they agreed to become a symbol to rally the citizens around for the coming conflict and a force to help, They would become false space marines.
The Iron fathers made cybernetic enhancements to each other and the sons of thunder and worked feverishly to the create workable power armor and weapons from scrap. The sons of thunder trained and healed as the incursion grew closer. As the ships grew close and the day was on hand the newly minted “Sons of Iron” emerged from hiding and boarded their makeshift transports. They made for the predicted incursion points, the imperial crests on their transports eliciting cheers from the hive citizens they passed. As they reached the surface the incursion began.
At first it was only them and they were pressed to their limit merely holding back the chaos tide with shotguns disguised as bolters and makeshift power armor. Soon when they were about to break the gangers came. There was a tide of slapdash armed longtime rivals marching to the surface under a makeshift imperial banner. With the changes to the sons of iron and the numbers from the gangers, they were able to repel the invasion and save Aurum. They looted a lot of good equipment and even a couple of interplanetary ships from that battle, though they demanded some cosmetic refits to avoid being seen as incoming chaos.
That was the beginning of the chapter and since then they have been continually updating and recruiting from the more noble of the gangers and the more skilled of the techpriests. In time they expanded their protectorate to the surrounding areas and reclaiming many or the worlds taken in the initial invasion. They wear the bare metal of their power armor with pride as a reminder of their humble beginnings and a gold shoulder to remind them of the home that they fight for. They keep their origins a tight secret even from the people of Aurum for fear of the inquisition and try to avoid contact with real marines but have fought with them on several occasions.