Reincarnated With A Summoning System

Over an hour after the news of the invasion came in, ten thousand troops were finally sent out to intercept them. As far as they can tell, none of the convoys have made it to the border yet, though nine different groups leading prisoners are being tracked. 

Since the Primordial Echo was mentally scarring the locals, Cain decided that it would be better if they went on the offensive instead. Heading East into Niman Territory, they split apart to cover more ground before transforming into Primordial Demons, or Demon Progenitors as the surviving members of their species are more commonly known. 

The first Echo turned slightly north towards where they detected civilization and called forth an entire army of Wrath Demons, including the Axe Wielding Legendary Quality Demon known simply as Carnage. The second followed the road southeast, hoping to find a larger city to compete with its twin, using an army of Succubus and other Obsession-type Demons.

The Demons they called were just as thrilled as the Primal Echoes to be able to let loose in combat, and a faction on faction competition gave them an extra dose of motivation. The only sad part of the Echoes day is that they couldn't clone themselves again to get armies of Magic and Plague Demons in on the fun. Instead, they'll switch factions tomorrow if they're still allowed to run wild. 

The first to arrive in a populated area was naturally the Wrath Demons, smashing walls out of houses and tearing apart public buildings to get at the people inside. The location they found was a small slave market village made up of quickly packable Yurt-style tents in bright colors and pens full of enslaved people from a variety of species set up in a hollow between hills along a well-worn path.

Almost all the defenders who would typically be here are out in Skyview on the attack right now, leaving them with no effective defense against an army of angry Demons. 

They didn't come here to beat up weaklings. They came looking for a fight. It's not long before the village leaders notice that the Demons are ignoring the slaves unless they're attacked and try placing inactive collars on themselves in an attempt to escape a brutal death. The Wrath Demons aren't stupid, though, and this feeble attempt at deception only makes them angrier and the deaths more brutal. 

The Echo, enjoying its time in the form of a Demon Progenitor, put its mind to hunting the leader of the camp, as it had become obvious no good fights were to be found. At first, it searched tent to tent, then a flash of inspiration struck its mind. 

"Tiny slave, where is your master?" It asked a Beastkin child who pointed directly at a haystack, following the camp leader's longstanding direction, to lead potential customers to him. 

The Echo doesn't even bother equipping a weapon, though it can use what Cain himself currently has equipped. Instead, it just transforms its own right arm into large tentacles and smashes the haystack until the straw is all red and the slave collar falls off of the helpful child.

"Thank you, little one. Tell the others that Duke Cain of Skyview sent us here to free you, and they should know where to go." The Echo says, patting the boy's head with the one remaining humanoid looking hand. 

It's getting quiet; they must be running out of targets, it thinks, tasking the Demons to find the last few and then follow it down the road looking for a better fight. They might have struck out at the first stop, but they are not giving up on the competition already. They've got until morning to find more targets. 

To the south of the rest stop along the trail, the Obsession Demons are in luck. An actual town, of sorts, has come into their view. It has a 2-meter tall low wall of local stone, a dozen or more guards along the walls, and over a thousand nonslave residents.

Perfect. 

The competition wasn't to free slaves, it was to kill slavers, and this border fortress was full of them. They have some slaves around for cooking, cleaning, and other purposes, but almost everyone inside is a trained soldier. 

"Oath Breakers, you go up and clear the guards from the walls. Once they're down, the rest of us will move in." The second Echo directs their troops. 

 They chose Lesser Succubus, Succubus Pain Bringers, a whip specialist with incredible speed, Oath Breakers, and a Legendary Demon called the Mistress of Pain. She's a Lamia-type Demon with a variety of cruel-shaped blades and barbed whips in her arsenal, as well as an Affinity for mental magic that is well known to break minds. 

A short stone wall is no obstacle for any of the summons present, and within seconds of the order being given, the guards are all down. The Demons charge into sight and enter the village, brutally killing everything that moves.

The slaves, for their part, are too terrified to do even that much. Teleportation and Demons mixed were well beyond their acceptable risk level, and they've all opted to hide and hope that being perfectly still will make them invisible.

The sounds of Demonic laughter almost drown out the screams as the defenders form into a circle in the middle of the fort. Many were caught off guard by the fast-moving Succubi and killed before they even got out of bed, much less understood what was going on, but now they've had enough time to prepare for a good battle. 

"Why are we under attack by Demons? The Demon Kingdom is over a thousand Kilometers from our borders?" One officer shouts as if someone will have an answer. 

"Mercenaries, they've got to be Skyview Mercenaries. One of the Dukes must have sent them." Another calls back, firing off arrows that drop Lesser Succubus one after another.

In a circular formation with s shield wall forming the outer ring, they're well guarded against the whips and blades of the Lesser Demons. Still, with the Oath Breakers just appearing, tearing their chosen target apart, and then vanishing for random lengths of time, their next victim is almost impossible to predict.

The defenders are not entirely done for, though; they outnumber the Demons by ten to one even with their losses. Their mages trap a pair of the Oath Breakers, and the others kill them. They repeat the process as the Succubus infantry dashes in and out, placing vicious attacks against their ranks and retreating to avoid retribution. 

For now, they can heal through that, and the attacks by the Oath Breakers are slowing, as most have been killed. The Mistresses of Pain, as well as the Primal Echo, are just waiting for the perfect moment, the time when the defenders believe there is hope, to move in and crush them for maximum satisfaction.

A cheer goes up in the defenders as the last Oath Breakers fall, and the outer circle expands to take the fight to the Succubus warriors. That's when the Mistresses of Pain attack, sending a cloud of crippling poison from a half dozen directions at once, filling the central areas of the camp. 

The poison does very little damage. Instead, it paralyzes the target and leaves them in incredible agony while it slowly increases the sensitivity of their pain receptors. It's not from the poison that they get their name, though. It's from what comes afterward. 

As the defenders fall to the ground, unable to move, the snake-bodied Demons move forward, barbed whips targeting fingers, nipples, and faces, tearing flesh and appendages free in a flurry of sensory enhanced agony. Then when they finally reach their fallen foes, they either crush them with their bodies or inflict a fatal strike and put them out of their misery. 

Usually, they wouldn't be so abrupt, but they're on a mission, with things to do, people to kill. 

A group in the center still has an active Healer and has dispelled the poison cloud, doing their best to fight off the new group of Oath Breakers. The fear and desperation are nearly an aphrodisiac to the Demons, who circle the last living defenders to watch the show. 

Most of the slaves of the fortress are already free, the Commander and most of the officers had fallen in the early stages of the battle. They're mostly still too terrified to move, hoping that the Demons will kill everyone else and then go away. 

But when they see the form of a Demon Progenitor wander across the courtyard eating popcorn, all sense of restraint flees them, and they make a break as one group, running out the gates and down the hill towards the Skyview border. 

"Oh, very good. They're even running in the right direction." A Mistress of Pain commends the Echo, who offers her some of his recently pilfered snacks. 

"Excellent work, everyone. I don't see or smell any more living people hiding in the area, so we must have gotten all the leaders. Make it quick; we've got things to do." The Echo instructs. 

The last few defenders break at that announcement, charging wildly at the Demons in a glorious last stand. Mighty blows rain upon the Demons before the brave defenders are cut down from behind, leaving only one single mage standing. 

He raises his dagger, blade to his chest, and thrusts, before finally wailing in despair, as his hand is caught in a large bronze skinned one with golden rings on its fingers. 

"Oh no, little mage. We've got a pretty new collar for you, and the Mistresses need a plaything to keep them entertained as we travel." The light of hope fades from the mage's eyes as the words of the Echo sink in.

Life as a pet to the Obsession Demons is a fate far worse than death.