DC Ruins. The Capital Wasteland.
The ghoul settlement called The Underworld was home to many ostracized non-feral ghouls who lived in what was left of Washington, D.C. What had once been part of the Museum of History was now a proper settlement complete with a bar, inn, clinic, general store and even a self-proclaimed hair stylist. While the ghouls tolerated most outsiders The Brotherhood of Steel were not welcome in these parts because of their hostility towards ghouls and their tendency to shoot them on sight, perhaps because they thought them to be feral and couldn't tell the difference, or maybe they simply didn't care to.
At least the super mutants left the ghouls alone, or they had until some new humans had turned up and started supporting the Brotherhood, between them they'd killed or driven off the mutants that Brotherhood seemed to be have been fighting forever. Willow, the ghoul who patrolled the entrance, hadn't minded at first, the lack of gunfire and explosions only made it easier to perform her role.
She could only assume that all the fighting had damage her hearing because how else could a squad of warriors in power armour sneak up on her. These were not Brotherhood soldiers this was something Willow realised right away. These humans, if they were humans under all that metal, each wore a suit of armour more ornate and clean than anything the Brotherhood had ever been seen in. The armour was mostly black with gold edging and the all had strange symbols upon them. Mostly some sort of fancy bird and a skull.
There were only five of them and yet Willow somehow understood that they were more than enough to destroy all the ghouls of Underword and to destroy everything they'd built.
"Mutant" said the leader of the power armoured people.
The female voice that came from inside the suit was full of hate and menace with no mercy. Something Willow experienced first hand when she dropped her weapon in an attempt to surrender. This did nothing other than make her an easy target.
Palatine Brigicia of the Adepta Sororitas looked down at the corpse she had made and then over at the four battle sisters that she brought with her to cleanse this small hive of mutant scum. Behind her stood Sisters, Decine, Sabedes, Hildes and Belloya, who like her had given up any family ties they had long ago and had even chosen new names.
Like her they were in the service of the Rogue Trader known as Lord Captain Thrax. Normally Battle Sister would not serve a Rogue Trader it was just that Thrax had earned the favour of the Emperor's most holy servants by casting down many heretics and then going on to bring an entire world into the Emperor's light. Back then she'd been playing the role of bodyguard for an Inquisitor as a lowly warrior. In time the Inquisitor had stopped needing her as he'd gained many soldiers who could carry out his bidding. Given how little the Inquisitor had shared of this plans for all Brigicia knew he was on the world called Planetos performing his duties.
Now she command entire squads of battle sisters and Lord Thrax had brought them to yet another world that badly needed to be cleansed in holy fire. While the Palatine could take many more of her sisters into battle with her she'd deemed that she would only need half a squad as the servo-skull sent to scout out this location had failed to find any meaningful defences. The mutants would pay for their lack of foresight.
The Palatine also wanted to preserve the strength of her sisters as there were not many of them and while dying in the Emperor's name would be a good ending for them she'd rather that her missionary live to carry out the Emperor's Will. This was why most of the sisters remained on the cruiser and why they were training any young girls they could recruit.
As the half squad of battle sisters entered Underworld they cared not at all for the businesses and the homes that the still intelligent ghouls had created for themselves. They saw only abominations that needed to be cleansed with sword and bolter. Palatine Brigicia slew a female mutant who cowered in her store and didn't even fire a weapon in her own defence despite having a supply of them. She didn't waste a bolt, instead swinging her chainsword and ending the mutant's life.
Others did try to protect themselves, they opened fire with their crude stub guns. Alas for them the power armour worn by the battle sisters protected them against such weak weapons and what cover the mutants could take offered no defence against bolters which blew apart anything their projectiles impacted against.
Such was the ferocity of the attack that it was over it mere moments and the sisters spread out so as to finish off any who hid. Palatine Brigicia soon entered what could have been a place of healing if not for the fact that it clearly not clean enough and it contained no injured people aside a young human female.
"What did they do to you?" the Palatine wondered.
She must have been captured by the mutants to fulfil some sick need of theirs. She was in some sort of coma and she might have been the subject of heretical experiments. Brigicia decided to be merciful and grant this woman a quick death before she ordered all of the mutant settlement put to the torch.