"Major Xavier! Geth incoming at heading two-five-three!" shouted Holloran, the corporal he had assigned to Tactical Control.

Michael swore, ducking low behind the barricade. "Get Felps on it," he snapped. He risked another look over the pitted storage container, and ducked back immediately as a hail of shots cracked into the barricade. "And where's frigging Lex?"

"Pinned down at one-forty, Major," replied Holloran. "Armatures dropped in almost on top of his squad."

"Frig." Michael levered his rifle, a new-ish Banshee VII, up over the top of the barricade and pulled the trigger. It bucked against his wrist with the recoil, but he thought he could hear the Geth stop firing for a second. "Is anyone at all free?"

Holloran checked. "No sir. We're under attack from every opening."

Michael set his rifle on the metal decking beside him and pulled out a grenade. He'd modified them with high explosives – he'd yet to meet any biomechanical chicanery that could compare to a simple explosion – and he hurled it over the barricade as hard as he could, hoping the Geth wouldn't manage to shoot it out of the air. Synthetics were too frigging precise like that.

They didn't, even though the weakening barricade was momentarily free of impacts while they tried, and the grenade detonated with a sharp thump. The metallic tang of the explosives filled his nostrils. He risked a look over the barricade. The Geth had been caught dead by the blast, scattered across the decking with ragged rips in their armoured carapaces.

He turned back to Holloran. "Right. Where the frig is Polonez and that damn Mako?"

"Uh… transponder puts them… three clicks out from the Colony, and closing. Whatever it was out there, they're heading back in."

Michael thought for a moment. "Get a wing of combat drones up to support Lex. Contact Polonez, and reroute her here. We need that Mako. Is Graver still at the ridge?"

The ridge was the local name for the outcropping of rock that ran the western edge of the Colony, a three-kilometre barricade. Graver and his squad were positioned there, holding off a swarm of Hoppers trying to scale the cliffs.

"Yes sir. Still under heavy attack, but he hasn't encountered any Geth heavy support."

"Give him the EW drone wing and tell him to hurry the frig up!"

"Yes sir."

Michael glanced around the container. A dozen Geth rounded the warehouse ahead. Behind them came an Armature, walking steadily forwards on its four segmented legs. He pulled his head back in.

"Damn Geth," he muttered. Holoran was too busy conveying orders to notice. Michael checked the surroundings. He had been pushed back to the supply entrance, surrounded by damaged warehouses and piled cargo. To his left, the customs tower rose up between two squat garages. To his right, more warehouses.

He tapped Holloran on the shoulder and motioned for him to stay put. The Corporal nodded, still speaking, and Michael tossed another grenade over the container towards the Geth. While they were distracted, he broke cover and sprinted towards the tower. They noticed him before he got halfway, and shots started to lance towards him. He ducked low, praying that none of the blue trails hit him.

He reached the corner of the tower, and pressed himself to the wall, his breath coming in heavy gasps. Nothing gave as much of a buzz as being shot at and missed. He scanned the wall. The door. Where was the damn door to the tower? On the front. Facing the Geth.

Frig.

He activated his omni-tool. The holographic display materialised around his left arm, and he keyed the waist of his armour with it, overcharging his kinetic barriers. It wouldn't last long, but the increased charge would mean the shields would recharge quicker. Maybe even quick enough to keep him alive.

Bracing himself, he took a deep breath. Now or never. Do or die. Or maybe do and die. Another breath, and he dodged around the corner.

The Geth had reinforcements. Another twenty of them scurried around the feet of two Armatures. A Juggernaut marched behind them, firing a steady stream of shots into Holloran's rapidly-disintegrating cover. They saw Michael the instant he rounded the building, and his shields flared almost solid blue an instant later under the sheer weight of fire.

The door – where was the frigging door? There! He ran for the centre of the tower, and the rectangular doorway there, hoping his shields would hold for just a little longer. They almost did. His hand slapped down on the illuminated panel beside the door just as his shields sputtered and failed. The door hissed open, and he fell through, hissing in agony as lines of fire scored across his side.

He tumbled to the floor, and the door slid closed, blocking off the torrent of fire. He lay there, eyes squeezed shut, teeth ground together. Damn, but it hurt! He guessed that at least three shots hand gone through both his shields and the plates of his armour. He opened his eyes, drawing in a sharp breath. From the damage to his armour, it looked like it had taken more than a dozen hits.

The pain wasn't specific. It felt as if he had been run through a mangle; one disadvantage of armour designed to spread the force of impact over its entire surface. Groaning, he pushed himself to one knee. Holloran was on his own out there. He had to do something.

The gunshot wounds hit him as he got to his feet. Sharp, searing heat shot through his right thigh and lower back, and he almost fell again. Damn Geth. Gritting his teeth, he forced himself upright. His armour helped, slightly, and he was able to limp to the elevator at the back of the lobby.

It took him up to the top floor, and he staggered out to the balcony overlooking Holloran's position. Just in time to see a shot from the lead Armature penetrate the container and engulf the Corporal in blue light. The marine didn't even have time to cry out.

Michael swore, and slammed his rifle down on the edge of the balcony. The magazines at his belt were loaded with Mark IV AP rounds, designed specifically to combat synthetics like the Geth. He slammed one home, and took aim through the short scope.

His first shot took a Geth in the right shoulder, the three rounds punching through the synthetic and spinning it around. He adjusted his aim, and fired again, sending a burst into what passed for its face. He managed to get another before they worked out where he was and started firing back.

He had time for a quick snap-shot that hit nothing before he was forced to duck low behind the balcony wall as the Armatures fired. He gritted his teeth. The damn Geth had killed his entire squad, along with half the damned Colony.

It had been two years since the Saren Upheaval, as the new Council had dubbed it, and the start of the Geth Wars. Until now, the Geth had confined themselves to guerrilla tactics, striking minor, undefended worlds and fading away before retaliation arrived. This time was different. Antola was neither minor nor undefended; being home to an Alliance environment-training facility, as well as a substantial population of civillians; merchants, farmers and miners eager to exploit the verdant world's natural resources. No, this time the Geth had struck in force, and as far as Michael could see, they weren't retreating.

The sound of a roaring engine made him risk a glance over the balcony. A handful of shots scattered around him, but he paid them no attention. His eyes were locked to his rapidly approaching rescuer. His battered, silver, eight tonne rescuer.

Lieutenant Polonez's Mako barrelled through the narrow gaps between warehouses and storage depots, its machine-gun chattering loudly. Geth dove for cover, scattering away from the rampaging vehicle. A few shots skittered harmlessly across its shields, but Polonez's driver ignored them, skidding to a halt between two warehouses, its turret swivelling to target the Geth beneath the tower.

The back ramp slammed down, and something huge and black emerged.

It was nearly as tall as the Mako, and armoured in plates thicker than Michael's arm. Its hands were enclosed in armoured gauntlets and as he watched, four crackling blades slid out of each one, like claws. Red gleamed in its eye lenses, and it charged.

The Geth shifted their aim to the charging figure, and round after round slammed into its huge chest. The man – if it was a man – shrugged the shots off, his armour proof against the impacts, and reached the Geth in seconds. He moved faster than Michael would have thought possible for something that size, smashing one claw into the chest of a Geth and tearing it brutally in half.

He never stopped moving, his deadly claws slicing and gouging with horrific ease. Behind him, Polonez's squad had emerged from the Mako and taken up firing positions, adding their shots to the black-armoured killer's tally.

The killer reached the nearest Armature at the same time as it fired. He didn't even hesitate, breaking into a roll to his left almost instantly, dodging the shot and coming up in a powerful leap. He collided with the Geth in mid-air, slamming his claws down into its back. They punched clean through the quadrupedal synthetic, and his momentum carried them both to the ground.

The killer was the first to rise, and his claws descended again and again into the Armature's body, sending scrap metal and sparks flying. When it stopped kicking, he rose, and smashed his right claw down into the centre of its head.

Michael almost couldn't believe what he had just seen. This monster had come from nowhere to take out an Armature alone, hand to hand. The damn things usually took explosives to even damage them, and this guy took one out with a claw?

And he wasn't done yet. As soon as he had his claw free of the Armature's head, he exploded back into action. Any Geth that got near to him died almost instantly, those deadly claws shearing through the synthetics' carapace like paper.

But the Armature had bought the Geth enough time to bring heavier firepower to bear. Michael saw the Juggernaut stop, sight on the charging killer, and fire its rocket launcher in the space of a second. He saw at the last moment and tried to dodge, but the rocket smashed into his shoulder and detonated in a crimson flash.

He was thrown backwards by the explosion, his thick shoulder pad shattered into fragments. The remains of a Geth crumpled beneath him as he landed heavily, and Michael heard Polonez shout something – 'Koroth'?

The killer; Koroth, from the sound of it, was on his feet instantly. He moved towards the Juggernaut, steadily gaining momentum. His claws smashed aside any Geth that got in his path, and his armour absorbed the Geth fire, though it was beginning to show damage now.

The Mako's turreted mass accelerator thumped a shot into the second Armature's head, and the creature died, thrashing about as its synaptic linkages flared and sparked. Polonez's squad turned their fire on the last Armature, whittling down its shields. It fired.

Koroth dove forwards into a roll, carrying him past the Armature's shot. He came up in a charge, surrounded by a blue halo from the Armature's weapon discharge. The Juggernaut advanced slowly to meet him, firing its weapons systems non-stop.

Koroth began to stagger under the constant hail of shots, but he reached the Juggernaut before any did damage. His claws slashed in from both directions, and the Juggernaut's arms fell to the ground, lacerated by the crackling blades. Koroth stepped up to the reeling Juggernaut and drove his knee into its gut, the force of the blow folding it over. He casually backhanded it with one clawed hand. The force of the blow almost took its head off, and sent it flailing to the floor several metres away.

Not content with disarming and disabling it, Koroth followed it and proceeded to ruthlessly tear it apart. Its chest fell apart under his claws, and its already-damaged head followed after. He tore off its legs and shredded them, then, as an afterthought, stamped one armoured boot down on its neck.

By the time he was finished, Polonez's squad, and the Mako, had finished with the remaining few Geth.

Trying to organise his thoughts, Michael rushed down to them as fast as his wounds would let him. As he emerged from the building, Koroth reacted instantly, dropping into a tense stance, claws bared. Polonez signalled him down, and the armoured soldier retracted his claws. Michael swallowed, and approached her.

She threw a salute as he got near. "Lieutenant Mischa Polonez, reporting for duty, Major."

Michael returned the salute. "Good to see you back, Polonez. You saved my ass here." He dropped his voice. "You and that giant, anyway. Who – what – the hell is he?"

Polonez was about to reply when Koroth strode over to them. "Do not try to conceal your words from me, Major Xavier" he said in a deep voice. "Secrets beget lies; lies beget vengeance."

An overpowering feeling of weakness washed over Michael as he stood in Koroth's shadow. Michael was six foot three, and even he was dwarfed by the warrior. Koroth must have been almost nine feet tall. How he had managed to fit in the Mako along with Polonez's squad eluded him.

Michael mustered what resolve he had, putting all the steel he could into his voice. "Fine. Who are you?"

Koroth looked down at him. "I am Brother-Captain Koroth, of the Deathwatch, formerly of the Raven Guard. I am the Emperor's will made flesh. I am Astartes."

The Emperor? Who? "I see," said Michael. He turned to Polonez. "Was he what you found in the desert?"

She looked uncomfortable. "Him, and four others, sir. They are following on foot, but from what I saw of them, they should be here in maybe five minutes."

Four others? Four more like Koroth? "Where the hell are they from?" he asked. Koroth certainly sounded human, but nothing even remotely like him was part of the Alliance.

"I am not of this galaxy," interrupted Koroth. "My Kill-Team followed a xenoform through its portal, and it led us here. The portal closed before we could return."

"Not of this galaxy?" echoed Michael, disbelief on his face. "Well, what, and where, is this 'xenoform'?"

Koroth stared at him, expression unreadable beneath his helmet. "Dead."

"They said it was a 'Necron', or something," explained Polonez. "It looked sort of like a Geth – what was left of it, anyway."

"Could it be a new type of Geth?" Michael mused aloud. "Or have the Geth branched into an intergalactic civilisation beyond the veil? But then how would they cross the dark space between galaxies?"

"It is not one of these 'Geth'," said Koroth. "The Necrons are far in advance of the Geth, technologically." His claws slid from their sheaths again, although their crackling energy fields did not activate. "Now, it would appear you have a xenos infestation on this world."

"The Geth have attacked, yes," nodded Michael. He thought that was what Koroth was referring to. "My marines are holding them back so far, but if everywhere comes under the same sort of push as we just saw here, then I doubt we can hold until reinforcements arrive."

Koroth scanned the buildings around him. "Then we must go. This world may not be part of the Imperium of Man, but, Emperor-willing, it may be in the future. These alien scum must be cleansed from the stars. I will subordinate my Kill-Team to you in this instance, Major Xavier, due to your knowledge of the area, and of the enemy. Where do you need us?"

Michael thought fast. Where did he want to put the… Deathwatch..? Everywhere. He didn't trust them yet, but their talk of an 'Imperium of Man' gave him the impression that, wherever they came from, it was no slouch at warfare. "Can you calibrate your navigational devices for local settings?"

Koroth nodded.

"Right. I want one of you at each of the following headings; one-forty, supporting Lieutenant Lex and his squad; two-five-three, supporting Lieutenant Felps; six-eight, supporting Corporal Graver; three-oh-two, supporting Gunnery Chief Adzen; two-two-one, supporting Lieutenant Polonez. Got that?"

Koroth nodded. So did Polonez. From the corner of his eye, Michael glimpsed four huge, black figures slide from the shadows between warehouses and head towards each of the co-ordinates he had given. The rest of Koroth's Kill-Team.

"Good. Move out."