Hello there everyone! As promised the invasion is now commencing, and (if everything goes as planned) there will be a lot of action sequences in this chapter. But before that, responses to reviews:

-hellisonfire345: Thanks for all the suggestions,, an Oriental Empire will be present in the future, as well as a Falmartian collaborationist faction, also 15.000 is just the first wave, {MINOR SPOILER ALERT} once reinforcements from offworld and Earth arrive and subjugated armies will be 'retrained' that number will rise sky-high.{Alert End}

-Davin111: Thanks, for both liking this story and the fighter suggestion, I'll might need more stuff in the future so I'll be sure to notify you when that happens

-TheQuestionedOne: Thank you, I checked them out, we'll see what I can come up with in that aspect, as for tanks, well... The striders and crab synths kind of fill in that role, so I don't think a new one will be required for quite some time

-Kamerad Hans: I completely agree, but I don't think there'll be a lot of covert-ops here, not 'spectacular' enough to impress the Combine, they didn't really do anything like that when they invaded Earth as far as I'm concerned. As for the suggestion for fighter, thank you, the idea sounds really good, some elements will be incorporated into the "final product"

-HopefullyHelpful: No problem, dude. Your suggestion sounds really good, thank you very much, but I don't think there's enough time for that in between the invasion and call to arms by the Empire. But it definitely sounds interesting, I'll make use of it in the future with another (set of) nation(s).

-Lex: Thank you, interesting suggestions, honestly, I kind of based the Combine fort on Lambda Wars combine buildings and the like, as for the thing with the gods, that definitely sounds interesting, maybe I'll incorporate it in some way into the story

That's it for now, and without further ado, here it goes..

Falmart, legionary fort at Alnus hill, 3 weeks after the expedition into the Gate

Sextus Galba arrived back to the fort just in time to see the 6 promised legions arrive, marching in a long column. It was a glorious sight to behold, 36000 legionaires and auxiliary warriors, hardened veterans from many campaigns, stretching as far as the horizon. With the 3 remaining legions at his disposal he now had command over 54000 men, but the legions came with a gift, specifically 15000 gifts; 15000 mercenaries that the legions could get their hands on on their way to the hill, including, but not limited to elven archers, dwarven pikemen, orc axemen, ogres, and goblin javelineers, slingers, and other skirmishing light infantry. The latter 3 unsurprisingly needed very little payment, the promise of carnage and loot being enough payment, with this he now had 69000 men. That, he believed, was more than enough to hold the enemy in place. With his camp being a mere 800 meters from the Gate, he could rapidly deploy his troops, encircling the enemy before they had time to deploy from the Gate, and thanks to the narrow confines, would be bogged down and eventually massacred.

His train of thought came to a halt when he saw Claudius Tullus approaching him, saluting before speaking.

"Legatus, a word please, I have reports from our scouts that I think you should hear."

"Yes Tullus, what would be it?"

"Our scouts report human-shaped transparent ghosts in the forests around the hill, only their eyes and mouths were clear. When the scouts went after them they only came up with nothing, or they didn't come back."

"Keep this from the men a secret for now, especially from the 3 legions that were originally here, we have enough problems with morale as it is. The only exceptions are our scouts, but you must make them swear secrecy about this before you tell them this. I trust you already know about our battleplans once the Otherworlders come?"

"Yes Legatus, the men are drilled and know their place once the battle begins. I have also taken the liberty to send messengers to the other legates and mercenary commanders to tell them about our plan."

"Very good Tullus, if everything goes as planned victory will be ours. Saderas Invicta!"

"I agree, Legatus. Saderas Invicta!"

Meanwhile, inside the camp

Flavius was not liking the situation, not by a long shot. Everyone knew that the Otherworlders would retaliate. It was just a question of when, and with rmours from the scouts circulating the camp about ghosts watching them at every opportunity, he was getting more and more sure about an attack coming. Of course, they had plans. Encircle and charge the enemy before they even knew where they were, and slay them in close-quarters combat. Of course the generals came up with this idea, they weren't there when they were fighting on the other side. They didn't see those blue and orange-eyed demons striking into his centurion's scutum with the back end of their staffs, breaking his shield arm and neck in the same way, in quick succession, they didn't witness a full plate-armored knight getting impaled by one of those 3-legged gigantic monstrosities.

The generals weren't blind to the fact that an attack is certain at any moment, and ordered their men to sleep in their armor, and their arms within their hands' reach. But even so, the more time passed, the more he understood why Cornelius fled. The waiting and the tension that came with it slowly grinded his nerves to dust. Right now he was getting ready to sleep in his tent with the 6 others in his contubernium, the last thing he layed eyes on before he fell asleep was the empty bed of Cornelius. If Emroy sees fit, they shall have one last peaceful night.

Earth, City 17, Sector-C1 central plaza, 3 weeks after the opening of the Gate

The invasion force has been assembled. 15 000 soldiers, veterans of many excursions into the wilderness beyond city borders and safe zones, into rebel-controlled zones, infested areas by various Xenian lifeforms, oftentimes the latter two were one and the same. And they survived, not only that, they were triumphant, further solidifying humanity's place within the Union. Soon, they would take their next step on that route. There were only minutes remaining until mankind's next giant leap that would be their saving grace from extinction, advancing humanity to a new era.

All of the troops were awaiting the order, the plans were drawn up, everyone knew what they were about to do, the only thing missing was the green light. That was until a podium was brought in, then Dr. Wallace Breen showed up, and took his place on it, the Consul and his guards at his side. The Administrator of Earth would address them directly, and the troopers eagerly listened.

"You have been selected for this operation as the best humanity has to offer. However, while our Benefactors and I have no doubt about that, especially after the major blows you've dealt to the Resistance, there's still one more thing we must do to prove ourselves as an indispensable part of the Union. I have done my best to convince our Benefactors that you are the perfect candidates as proof for that. The burden of proof now is upon your shoulders, and the chance to prove it is behind me, in the so-called Gate. Immortality of our species has never been closer to us than in this present moment, and with your help it will only come closer and closer, until the day of a new age for our species will dawn, an age where we're truly part of the Universal Union, an age where the threat of extinction is but a distant echo of the past, an age where humanity's full potential is discovered and put to the best possible use, and to achieve that, I only request one thing from you, members of the Transhuman Arms of Earth's Overwatch. Serve! Serve mankind! Serve the Universal Union!

The response was a unanimous, perfectly synchronized salute, the sounds of which echoed throughout the streets. The Administrator stepped down from the podium, whose place was taken by the Consul.

"Several of our Special Forces Teams have been deployed to the other side. According to their reports, there's a large enemy camp just outside the deployment zone, therefore contact with the enemy is to be expected from the moment you reach the other side. Once the engagement has begun, special forces will target the enemy leadership, your task is to defeat the enemy main force, fortify the other side, and stand by for further orders from your commanding officers. That is all."

Following the consul's briefing, the podium was removed, and a message was relayed to every Overwatch soldier.

::All units, invasion is a go, repeat invasion is a go, stabilization teams, Savage, Payload, Sweeper, Dagger, Hunter, Hammer, Mace embark, and make crossjump.::

The troops assigned to the first wave embarked into their APCs, while 10 Crab Synths went into the gate in a 2 by 5 column, followed by 10 Striders, 'crouching' and in single file. The APCs were bringing up the rear, with more troopers being on standby ready to assist their comrades in a moment's notice.

Soon, the darkness of the gate enveloped them, the only sources of light were the APCs searchlights, but only that was needed. The synths could make their way even in total darkness. Soon, a light was seen on the other side that kept expanding. Every one of them knew what that meant. The light soon became blindingly bright, and the first pair of Crabs crept out of the portal onto a hill, the nighttime sky above them filled with thousands of stars. They were followed by their brethren and the Striders, once the APCs arrived and the soldiers within them quickly dismounted, taking up positions around the Gate, the first wave forming a crescent around the portal.

:Weapons off-safe, report all radials free.:

At that moment, the entire base of the hill lit up with the flames of thousands of torches, silhouettes of wverns visible above them.

:Viscon viscon, bearing 270 to 40 degrees, range 800 meters!:

:Overwatch Sector 1 is infected, repeat Sector 1 is not secure!:

:Overwatch orders 6cc stim boost:

:Executing full response:

The calls and roars of Striders and Crabs were heard above the frantic radio chatter.

The sun was rising above the mountains behind them; the dawn of a new age. The Imperials were scurrying to and fro, quickly organizing into their formations, and advancing.

(Soundtrack: Something Secret steers us {extended remix 2.0 by System Overlord})

:Natives at 750 meters:

They advanced. Boldly, confidentially.

:Natives at 675 meters:

Why wouldn't they? The enemy were few, and out of formation. This would be a quick victory.

:Natives at 600 meters, fire weapons!:

On that day they were proven wrong. The sun rose above the battlefield, and all hell broke loose.

:Hammer 2, engaging:

:Hunter, suppressing:

:Sweeper Zero, firing:

Striders fired, Crabs let loose their underbelly pulse-gatlingcannons, tearing into the enemy's tight formations, causing devestating damage APCs added their own fire to the cacophony, all the while the soldiers let bullet after bullet fly towards their foes.

The legions quickly caught up to what was happening and quickened their pace, devolving into a mass charge towards the Combine forces. Soon even the resemblance of the previous orderly advance was lost in the stampede. All in favour of the invaders, their accurate fire killing by the hundreds. The wyverns fared better, flying undetectable. For a while at least.

:Enemy air inbound!:

The APCs shifted their focus, targeting their flying adversaries.

:Target locked, RPE away!

Rockets flew, hitting wyverns left and right, but some missed, and the beasts gunned straight for the Striders, which responded with close range pulse fire, one charging up it's dark energy cannon, hitting an incoming wyvern point blank, just in time.

Yet, in spite of all the damage they were taking, the enemy didn't give up, every fallen soldier's place being taken by 5 more.

:Natives approaching 350 meter mark!:

:En-extractor away!:

The few Elites fired the energy balls from their AR2s, cutting swaths out of the enemy's formation, which only seemed to enrage them more.

:Overwatch, requesting immediate reserve activation!:

After a short while reinforcements arrived. More soldiers, more Striders, Crabs, and Hellion guns, which were quickly set up by their crews. By that time the enemy was so close that even without augmentation the soldiers could see the white in the eyes of the charging imperials.

:Ready charges!:

:Extractor away!:

Grenades were thrown into the mass, sending body parts and dirt flying everywhere. Taking advantage of the situation, the Striders, like war elephants of a past(/present?) time countercharged the enemy, impaling some on their way, softening the enemy's charge up. The soldiers only had a few enemies making a break through the gaps in the Striders' formation to take care of.

From that point forward the battle devolved more and more into a chaotic slaughter.

Meanwhile

Small teams of Combine assassins were patiently waiting in the cover of the night, waiting for the signal to be given. Soon their main force started trickling through the portal. Naturally the Imperials engaged. Soon they too received green light, their teams stalking towards the enemy's rear lines and camp.

(Soundtrack: Opposing Force: Bust)

Under the cover of battle, they moved silently. Their targets were the camp itself and the enemy leader. They were to capture him. Alive. Under the watchful eyes of their snipers, the first team reached the fort's walls. The Imperials had left a token force defending the camp, in case they needed a place to retreat to. Currently, said guardians were watching the battle unfold, unaware of the ghosts encircling their camp. The few guards at the side gates were quickly dropped by the snipers, the assassins rushing inside, planting explosives below the walls, inside the barracks, storages and various other buildings.

:Charges armed and set, ready to exfil:

Just as quickly as they got in, they left, the unfortunate souls within the camp were completely unaware of their doings, until it was too late.

Meanwhile the second team was stalking the enemy Legatus and his bodyguards, who were directing or at least trying to direct the battle. Messengers were going to and fro, no doubt relaying orders to their cohorts and alae of cavalry. The time has come to cut off the head of the snake.

The assigned marksman loaded a tranquilizer shot into his rifle, aiming for the spot between the Legatus' helmet and armor, the crosshairs settling onto his unprotected neck. He fired and the shot flew straight, the Legatus immediately falling from his horse, rendered unconscious even before he hit the ground. Before his guards could react, they were cut down by silenced submachine gun fire from all sides

:Helix Vector Tango contained, ready for wrap-up:

The enemy didn't realize the disappearance of their leader until the orders stopped coming, soon the confident Imperials would turn into a panicked mob, desperate for an escape that would never come.

Just outside the Gate, Falmartian side

(Soundtrack: Black Mesa: Questionable Ethics 1)

:Natives on top of our radials, Overwatch we have encountered heavy resistance!:

The enemy was now within 150 meters and closing, the shotgunners, who were, until now, relaying orders to their squads joined the fray, sending pellets after pellets into the enemy's formations. This time, however their fire didn't go unanswered. Archer cohorts managed to form up, and loosed volleys of arrows towards the Combine positions.

:Displace!:

:Ripcord! Ripcord!:

:Dagger-4, one down, one down!:

Arrows were not the only problem the soldiers had to deal with, ogres dragged ballistas in range, which sent rocks weighing 100 kilogramms each flying towards the Combine lines. Luckily they were inaccurate, only sending a few soldiers scurrying away before the rocks hit. The Hellions gave their answer soon enough, entire batteries going up in flames, their crew vaporized in an instant.

At that point the enemy seemed to panick more and more, their Legatus were nowhere to be seen, the other Legates were killed by redirected sniper fire, orders were not coming, and the enemy fire just got deadlier the closer they got. That was when their beasts charged down the hill, impaling the few brave or foolish enough not to get out of their way. Suddenly a series of explosions were heard, those who looked back saw their camp going up in flames. The enemy got behind them!

:That's it! Wrap it up!:

Panick spread like wildfire, the a few of the remaining tribunes tried to rally the troops, but to no avail, once the first cohorts started routing, others followed suit, and soon the entire army chain-routed, pursued by Combine fire.

In just 2 hours, the Universal Union gained a foothold in a new world, the ones sent to oppose them either dead or too terrified to even speak about what happened that day.

Author's notes: And that's it for today folks, hope you enjoyed. Autumn break is coming to an end here, where I live, so I won't be able to post new chapters as frequently as I have in the past couple of days. Hopefully I'll be able to update the story weekly, but i'm not promising anything.