A series of disparate tactical decisions were made over the course of the next few days.
Here, a certain segment of the Xenos was shelled and diverted from their course. There, a thrust of the armored cavalry eliminated some of the Xenos fleshtanks, and psi-active gasses coated the streets in twitching carcasses of Xenos. An advance, enfilade, and carpet-bombing of a major horde sent Xenos spilling off in another direction. Lines of fighting fluxed and moved, an atomic bomb came down atop a fallen blok and reduced all the people within being devoured and converted to biomatter down to ash and blast shadows, and incidentally cleared out the neighborhood of anything living, too.
Lines of enemies shifted and pulsed with new reinforcements and advances, whole sections of the Underspires were slagged to deny them any passage beneath, firestorms sweeping death along passageways charged with alien invaders and hapless pslaves.
The Obsidian Serpents did a fine job of killing, sweeping in time after time to flank invading hordes as they expended themselves on entrenched defensive lines, taking a bloody and efficient toll with very few losses themselves, coldly ignoring the complaints of the defenders as they returned to their tasks and the killing.
But their sneaky ambushes and sweeping slaughters were all done now.
Squeezed out by the pressure of the horde and seeing an opening, a massive unit of Xenos had surged through a section of abandoned factories, seeking an opening in the defenses of the remaining humans, and stumbled right into the Obsidian Serpents. What had been a ready force poised to spring another ambush when the Planetary Guard advanced and drew the attention of the horde turned into the primary protagonist and target of millions of hungry Xenos their hivemind naturally recognized, and suddenly the sneak attackers had the full attention of a lot of eager Xenos.
Their doctrine didn't focus on withdrawals and fighting retreats, but they were powerful, intelligent soldiers, massively trained, and they worked together with the ease of long experience. Pulse carbines too heavy for a normal human to lift were their primary weapons, as they had to conserve the more effective heavy gyrolaunchers and their explosive payloads, but now it was retreat, retreat, retreat from the oncoming horde.
The tactical feed was also none too promising. Their paths of retreat to safe lines were cut off time and time again by surges of Xenos reinforcements moving in to block their path, or PG positions in other areas were surging and harrying, pressing the xenos back into paths that interfered with them withdrawing to safer lines. Relief forces were nowhere available, and even their dedicated gunboat that dropped ammunition and supplies to them was blown out of the air by aerosyms carrying plasmic postules, blown apart under the point-defense turrets and covering the gunboat in hyperacidic naptha, melting right through the hull and engines and sending it into a final tailspin into a food processing factory long cleaned out and torn apart by the Xenos.
The Obsidian Serpents were pressed back further, and further, and further. Here and there, syms managed to reach individual warriors and swarm them in a mass of black carapaces, phrenic claws capable of rending their armor and getting at the flesh within.
Through bombed-out factories, warehouses, and storefronts, through cratered streets festooned with blasted vehicles and hovercars long fallen from the skies, scrambling over the remains of collapsed pedways and highways, the Obsidian Serpents retreated, and undeterred by the dead being recycled by the cleaners among them, the Xenos pressed eagerly after them.
They were driven down a long avenue, heaping up the aliens time and again, and found themselves at a racetrack for deathbike games, a long oval of cement and seats with little recourse around them.
They retreated into the track, a single resupply ship managing to get through before flocks of suicide fliers converged and blew it out of the air, and their last-ditch defense against millions of swarming Xenos began.
-------
Bastrid noted that the Serpents left a mess behind them, as a shattered carapace crunched under his armored boot.
The last of the Xenos were being picked off impartially and precisely as his company of fifteen hundred or so drew the circle in tight and picked them off. The girls had set everything alight with vivus, and heavy unwhite fog was misting almost knee-high as shattered Xenos burned quickly and heavily, remnants of phrenic power meaning eager fuel to the fires of reality.
"Hold fire," he grunted out, and the firing stopped like a knife.
The last few Xenos were struggling with surviving Obsidian Serpents, and the call was a reasonable one, so they didn't shoot their allies. Desperate Serpents were hacking with knives, steaming with acidic gore that was corroding away their stealthslake and unit markings, and mucking up and destroying their armor's coating. Most of them had rent armor from the foreclaws or whipping tails of xenosyms, and any acid that got inside those locations had probably reduced the limbs and flesh within to goo. A good chunk of the surviving Legionnaires were probably swinging around power armor with nothing intact inside it.
There were a couple shots from the girls, tracking motion and shooting things trying to scamper away. Tych swung down with Stroke, and lifted up a kicking cerevore, like a pig stuck on a pike.
Twenty different Sun Shots blew it into ash and vivic spray in the next second.
"Control, this horde is dead," he reported calmly, as the last of the xenos was ripped apart by a big Legionnaire, flung aside as steaming remains of phrenic fun. "What's our next objective?"
Anatolia sent him marching orders, and he chopped and gestured. A few good-natured jibes rang out as guns were checked, fresh power clips put in, and the men lined up to exchange clips with the troopers wearing Mass Packs with fusion rechargers... which naturally included the Ranthas and Briggs Brothers.
"You! Captain!"
The booming voice of the Legionnaire officer almost had physical impact... but Bastrid couldn't have cared less, as he had Thunder resistance, and the loudest of noises was no more impressive to him then a whisper. He turned around as the Legionnaire in the wrecked remains of his officer's armor came striding over to him. Judging by the rent in his right thigh, he didn't have anything left from just above his right knee to his foot anymore.
He turned around coldly and looked down at the man.
That was impressive enough, because the Legionnaire was over seven feet tall himself, and easily eight feet in his power armor. Bastrid was eight feet tall himself, and in his power armor stood a head taller than the Legionnaire Captain... Kvimos, was it?
"What do you want, Captain?" he asked coolly, while the whole company stopped on a dime and turned to watch. The rifles they hadn't quite put away suddenly lit up with a display of golds, greens, blues, and scattered silvers.
With little stars and suns circling about them...
The Legionnaire Captain saw that, and there was a faint shift in his posture. He was fully aware of how dangerous Sun Shots were. Mentats, Coronals, and Umbrals using them had butchered the rebelling forces of the Progenitors, despite their power armor. Hundreds of Planetary Guard using them... if something erupted, he and his surviving Marines would be slaughtered in seconds.
He looked over the men and women staring back at him coolly, unimpressed, unafraid, and certainly not reverent.
He knew they were the same people who had fought back against the horde in the Coliseum a few days before, and instead of being grateful for their assistance, were obviously disdainful and arrogant. The fact they were competent he did not doubt, as he had seen them at work then and now.
In fact, were he honest with himself, he found the idea of facing them in combat rather daunting. Only with an ambush did he have any confidence in beating them in a fight.
"Your timing could have been better, Captain," the Legionnaire officer hissed, despite himself, fighting down his anger.
"My timing was hurried," Bastrid admitted casually. "I would have liked to have set up tighter lines, but we were in a rush."
The helmed Marine's lips were drawn tight. Hurried? HURRIED? Over half of his company was dead, everyone was wounded, and they were still in enemy territory!
"Now, unless you have business, with this arm of the Xenos destroyed, we've been redeployed," Bastrid went on calmly. "I think there'll be Xenos reinforcements coming through in half an hour, so you might want to move out before then."
The Serpent captain looked at his tactical feed, and could see the colors moving in from the north. He swore to himself... his company was in tatters, his battle brothers were lying in pieces all over the place, and they certainly didn't have enough healing crystals to treat everyone, while their gyro ammo was completely spent.
"My company is incapable of reasonably undertaking another engagement of size. I would like to request extraction."
Bastrid just blinked once. "There's none available. You're bloody lucky we were even close enough to do anything, and Tactical noticed the odd convergence of the horde here, and decided to wipe it. HQ is hardly going to set aside everything to evacuate a bunch of people who aren't even part of the strategic plan. You want out, you get up and find a way out, Captain, just like us."
Kvimos could only glare at him futilely. If nobody could come, nobody could come. "Do you have a path of withdrawal, Captain?" he managed to say coldly.
"No, Tactical sets up the withdrawal routes. We go where Tactical sends us," Bastrid replied easily. "Do you have anything else, Captain? We have a war to fight," he said, obviously eager to get out of there.
"Permission to shadow your force on the withdrawal, Captain," the Legionnaire asked icily, clearly planning to do it whether he agreed or not.
Bastrid just sighed. "Control, this is Captain Bastrid. The Null Marker, those Obsidian Serpent Legionnaires, are requesting they be allowed to shadow my company on the withdrawal. Uh-huh. Uh-huh. Uh-huh." He looked back at Captain Kvimos. "Tactical suggests that is unwise. They are moving in some artillery assets to cover us as we find a way out of here, and you might be shelled as the Xenos get closer. They suggest using your stealth protocols and finding another path that friendly fire won't threaten."
Kvimos gnashed his teeth. Their tactical command was effectively saying that since the Serpents didn't coordinate with them, they weren't going to coordinate with the Serpents, either. "I am willing to submit to the command of your Headquarters for the duration of this withdrawal, Captain Bastrid!" he offered.
"I am not relegating command of my men to you, Captain Kvimos," Bastrid stated coolly, "and I'm not going to be happy with an unreliable force on my flank." Kvimos bristled at the statement. "If you are willing to cede overall command to me as we get out of this, that's fine. If not, find your own path out, Captain." His voice was grim and final.
Kvimos stewed. A mere Planetary Guard, commanding Imperial Legionnaires? The whole idea was preposterous on the face of it. These Guardsmen should be begging to be commanded by and work with Imperial Legionnaires, the most elite troops of the Empire!
He noticed that whole sections of the group were turning and hurrying off at a trot, and realized that the hostile colors in his landmap were growing closer.
There was no time, and the Guardsmen who could keep his men alive were already leaving.
"I agree, Captain Bastrid," he finally conceded, although the words bristled on his tongue.