Author's Notes: Not a single credit was made from this fanfic. For personal entertainment only.

- One thing i'd like to forewarn readers is that my Shepard will be based mostly on my playstyle. For a bit of background- i've never been a big fan of cover-based shooters. I'm an old-school FPS gamer, from the original Doom to Unreal Tournament to Team Fortress 2. I've always felt movement was the best way to survive a (video game) gunfight, and more importantly, taking away movement is taking away half the fun. So I played Vanguard. Charge and barge all the way.

Chapter 1: The Sole Survivor

Riding in the M29A Grizzly was a cramped and bumpy affair. The Grizzly infantry carrier was designed on Earth, tested on Mars… but obviously the engineers didn't have Akuze in mind. "All Terrain" on Earth meant very little on this planet, but the colonists were eager to settle here anyway. Perhaps it was the bravado of conquering a relatively hostile planet, or maybe it was the glory of having their names being immortalized as the founders of the future flourishing Akuze colony they were envisioning. The pioneering colonists established a relatively well-protected colony along a stable, rocky mountain ridge with an intricate cave network and a good groundwater supply. Access to the landing site for supply ships required lightweight hoppers. None of them had to suffer the labourious affair of a forty-ton vehicle trying to clamber up the slope of the mountain they chose to settle on.

Then again, it was likely that they already suffered a fate much worse. The communications channel to the colony had been cut several days ago. Equipment malfunction was ruled out, as they should have had a backup; it had never been activated. Weather and mapping satellites indicated a clear atmosphere in the region. Something else was going on. Lieutenant Shepard thought it was slavers, raiders, or someone else of their ilk- and so did the brass. The numerous cave networks, mountains, valleys, and nigh-unnavigable terrain was a perfect place for outlaws to hide and set up shop. A full platoon of Alliance Navy might have been overkill for a simple colony investigation, but it might not have been enough if there were pirates using guerrilla tactics.

"Commander," Shepard turned to his superior officer. "The Redwind is still scanning, right? Has it found anything at all?"

Commander Burke shook his head. "They've increased the radius to 100km, and there's still nothing. If someone's there, they've got to be inside the caves. They did detect a little seismic activity and damage to the colony pods. Conclusion's pretty obvious, I think. The geologists were wrong, and the colony's suffered a pretty bad natural disaster. This is going to be a search-and-rescue mission."

Shepard nodded, mentally preparing himself. Sometimes, rescue missions were worse than assaults. At least in an assault, he was facing people that could be called "bad guys." People who generally did something wrong and had to be put down. With rescue missions, more often than not he was faced with the suffering of innocents, and in the worst case scenario, all his efforts would be futile to save them. Colony missions were usually one or the other. If it wasn't pirates raiding a hapless, fledgling colony, it was a natural disaster rendering the colonists helpless.

"We're getting out here," Burke announced. "Any further and the grizzlies will just get stuck. Delta team will secure this location. Alpha will head to the lower colony area, Bravo will approach from above." The teams exited from the tanks, preparing for a long march ahead.

Shepard took the lead for Bravo. As the vanguard of the group, his mass effect barriers could absorb far more damage than the standard, nanite-based kinetic barrier armour. Shepard in particular was more powerful than most other vanguards in the Alliance Navy. His father was a high ranking military officer who wanted to ensure his son grew up as a "real man"- to him, that meant knowing and learning about the latest and greatest (unclassified) gear and technology, assembling and disassembling real guns when other children his age were playing with toy guns. He suspected that, if it weren't against Alliance policy, his father would have offered him up as a test subject for the experimental biotic implant development. He'd already received the best civilian implants available at the youngest age possible, and combined with an asari tutor for ten years, it made him one of the best, if not THE best human biotic in the military. While he was by no means a genius or savant, having spent more time under the effects of eezo than professional biotics twice his age made his understanding and manipulation of biotic fields second only to the asari.

Shepard kept his barriers up and a pair of SMGs in his hands. Some others would have only activated them upon seeing an enemy, but his father had told him horror stories of failed raids and ambushes, deaths due to the half-second it took to activate a kinetic barrier or unfold a weapon. As bedtime stories. In these tales, the napping hare didn't just lose a race, it was skinned and cooked for dinner. Besides, he was a vanguard. In any ambush or assault, he was supposed to take the brunt of the initial attack, and lay down a hail of covering fire while the rest of the team could get to a better position.

Unfortunately, the attack didn't come from in front of them. In fact, Alpha and Bravo teams weren't hit at all. The unthinkable happened instead. Only a fool would have assaulted Delta team first, with their three armoured vehicles, each outfitted with 155mm cannons, in a highly defensible position with good sight lines. And only a monster could have been successful. The only warning was a slight tremor in the ground, just before screams came over their comms. Cannon fire sounded off in the distance, followed by the sound of screeching metal. Delta team didn't respond to hails over the comm.

"We have to secure our escape route. Find out what happened. Everyone, return to the grizzlies, double time!"

They arrived to only bits and pieces of wreckage. It wasn't a bomb or an explosion. There would be far more debris in the area. Something had shredded through ten centimetres of AN3 armour, the type of armour that could easily withstand anti-tank rounds and repair itself afterwards. Anything less than a compact nuke wouldn't have made more than a dent. They would have seen the mushroom cloud of a blast like that.

"What in the hell? Sterling, see if you can get any readings," Burke ordered the team's resident engineer over to the wreckage, while the others fanned out in an attempt to form a perimeter. Shepard surveyed the area. To the east was nothing but a sea of sand, which they had avoided on their approach. The grizzlies weren't made for such soft terrain. The colony was in the mountains the north, where they had just come from- obviously no enemies there. The mountains wrapped around the landscape all the way to the west side- wide, jagged terrain that could perhaps hide a few people on foot, but not the kind of heavy mech that would be needed to mangle the grizzlies into the mess of metal in front of them. The southern route was the flatter, packed rock where they approached from. Nobody was reading anything on their scanners. "Redwind reports no activity in the skies, either," Burke updated the team. "Wherever they are, they're on the ground."

Shepard knew that couldn't be right. He, and the rest of the team, could see everything on the ground, and the Redwind was covering everything in the air, and everything in orbit up to the third moon was easily within active sensor range. That didn't leave anything but… underground. But that was impossible. Unless…

"Uh… sir… you're not going to believe this," Sterling said, staring at his omni-tool.

"I'll decide what I'll believe. Tell me what you found," Burke replied.

"Only minor acid degredation. No thermal weaponry, no plasma, no mass effect warping. The grizzlies were sheared apart by brute physical force."

Brute force that could tear apart tanks? Popping out like the boogeyman and disappearing without a trace? It sounded like a childish horror story, but Shepard knew better. He grew up on starships. He grew up with, well, his father, who told stories like this all the time. He knew the difference between an old wives' tale and real horror. He heard tall tales in the mess halls. He heard real horror stories in the med bays. This particular story he'd heard just before becoming a teenager, and here he was, nearly twenty years later, living it himself. "THRESHER MAW!" he yelled out. "Everybody, up the mountain! Get on to solid rock!"

"What are you on about, Lieutenant?" Commander Burke barked at him. "We need to secure the area and search for wounded, not…" He was cut short by a distinctive rumbling beneath his feet. All the other soldiers looked uneasy.

No matter what stories they'd heard, whatever training they had, nothing could prepare a person for a five-metre-wide set of jaws bursting out of the ground, rising thirty meters high. Half of Bravo team was swallowed in one gulp. Commander Burke wasn't prepared to issue an order in this situation. The rest of the team wasn't prepared to follow them, if he had. Some stood, frozen in shock and awe, while a few others managed to find their trigger fingers and start shooting. Shepard's mind was frozen, but his body ran on instincts. A decade of hard training forcibly supplanted his natural urge to run in the face of danger, even in the face of impossible odds. Vanguards charge in.

Routing all his barrier power in front of him, he ran towards the towering beast, firing everything he had at what looked like soft spots, hoping to get its attention. It was a futile effort, the SMGs barely scratching the thick, chitinous armour of the beast. He slapped the SMGs back onto their magnetic holsters, pulling out his heavy shotgun and throwing up a biotic warp. The rapidly fluctuating field altered the density of the target hundreds of times a second in an effort to degrade and soften hard armour targets. One point three seconds. The shotgun was unfolded and ready to fire.

White hot lead shrapnel struck the thresher maw's plating. He'd managed to crack it slightly. Time to do it all over again. Four seconds until the power supply in his armour could fully charge his biotic amp capacitors. Three… Two…

The thresher maw shifted, spitting a ball of digestive goo at the largest piece of wreckage, where five of his teammates were taking cover. Their screams were painful. Their deaths were not heroic. Shepard could hear the sizzling as the grizzly's armour was being eaten away by the digestive juices. He could only imagine what it was doing to the personnel armour.

Zero. Shepard threw another warp at the same spot, hoping to break through to the soft tissue. At the same instant, the giant worm dove down to where it just spat, consuming the last chunk of metal. His target spot was suddenly fifty meters away. As the beast snaked its way back underground, it gave the survivors a glimpse of its true size. It must have been at least two hundred meters long. The little scratch Shepard put in it must have been as annoying as a mosquito bite.

Where was the rest of the team? Not on the mountain was the first thing he realized. Only eight marines were left, the remainder of Alpha team. They were grouped together, making a run for the colony pods. Shepard clambered up to a safer height on the rocky cliffs, yelling into the comms, "Get up here! It can't chew through solid rock!" At least, not as quickly, he hoped.

A few of them saw him waving, and dutifully changed course. Unfortunately, the thresher maw took that moment to burst out of the ground, narrowly missing the group. Had they continued forward, they would have disappeared into the maw's gullet. They were still far from safety, though, and Shepard's instincts kicked in. When allies were in danger, vanguards charge in.

Except the fact that he was standing high on a cliff- a hundred meters away and twenty up - was holding him back. There was no quick route to the thresher maw, no way to distract it from his squadmates. He had to get there. He didn't have time to think about it. In the back of his mind, the memory of his first mass relay jump bubbled up. He'd been invited onto the bridge by his mother, and he could see the stars change in an instant. He remembered the feeling of his second mass relay jump, inside the engineering core. Even without windows or star charts, he knew he was very far away after one second. He remembered his first mass relay jump after receiving his biotic implants. He could feel the mass effect fields warp the mass of the ship and space itself. The feeling was wonderful. It was powerful. It was why he spent so much time on the engineering deck as a child.

Only an idiot would believe it was possible to attempt a mass relay jump with little more than implants and a dozen amplifiers built into a suit of armour. Only a fool would actually attempt it without theorizing, experimenting, practicing, and developing the idea. Only an madman would use such a technique to get closer to a thresher maw. Only Shepard could pull it off. When allies were in danger, vanguards charge in. Shepard charged.

He weighed in at one hundred and fifty kilos, fully suited in armour. He suddenly weighed nothing. He was standing at the top of a cliff, a hundred meters away and twenty meters up, watching his teammates in front of him struggle to climb up the steep slope. His teammates were suddenly behind him, and the thresher maw took up his entire field of view. He now weighed in at nine thousand kilos, bleeding off the excess momentum simply by crashing into the half-buried beast. The biotic amps shorted out. He weighed one hundred and fifty kilos again. He was standing right beside the thresher maw. And he had finally caught its attention.

The force of a nine-ton human impacting the maw finally managed to make a dent in its armor. Shepard held the trigger down on his shotgun until it overheated. The swapping mechanism built into the forearm immediately replaced the thermal clip with a freshly cooled one. Lucky for him, thresher maws weren't that flexible. Very few things ever managed to get as close as Shepard did, and he was pounding away as much as he could with his shotgun while the maw could do nothing. Another thermal clip exchanged. And another. And another. Until his suit couldn't keep up with the cooling and started swapping in hot clips into his gun.

Shepard realized he was taxing his suit of armour to its power limits. He had to retreat for a minute until all the clips cooled off again. He'd never encountered this before- technically, he had let loose enough firepower to kill a full platoon of soldiers. And it was just barely enough to annoy and distract the beast. Well, his job wasn't to kill the thing- just allow his team to get to safety. In that respect, he'd been entirely successful. The team was standing on solid rock, higher up. He made a sprint for it back to his team. Half of his biotic amps were shot. He could barely remember how he managed to perform the charge manoeuvre. It didn't matter. The maw was retreating underground, and this was his chance to get to safety and return to his squad.

"What the hell was that, Shepard?" McKinley, second in command, asked as he caught up. They'd slowed down only slightly to let Shepard join them. As soon as Shepard caught up, they raised the pace again to the limits of their exosuits.

"I don't know. It felt right at the time. I'll figure it out once we get back to the ship," Shepard replied.

"Whatever it was, it saved our asses. Thanks, Shepard." The other marines mumbled in agreement, still in shock at the attack and the losses.

Shepard did a quick headcount. "Weren't there eight of you?"

"Jones, Armen and Toole didn't make it up here," McKinley answered. Pre-emptively, he added, "Don't beat yourself up about it. You did more to save our asses than any of us could have to our own."

No time for mourning. Probably no bodies left to mourn, either. Their dogtags were probably melted away too, just like the grizzly's armour plating. Survival was the primary objective now. "I guess Commander Burke didn't make it either?"

"He was one of the men taking cover behind the melted chunk of grizzly."

"So what now?"

"I've lost my connection to the Redwind. I don't suppose you could get one either?" Shepard shook his head when static came through his earpiece. "We figured we could activate one of the comm antennas at the colony. Safest place for a Kodiak shuttle to land is on the roof of the colony pods anyway. Anything lower and that damn maw would probably grab it out of the air. Probably a good dessert after eating three goddamn tanks."

"I always thought those were just stories made up by the turians to fuck with us," Tillman said. "Giant underground worms that eat tanks and can swim through dirt like an eel. What part of that makes any sense at all?"

"Space is a weird place," was the reply he got from Corporal Toombs.

"Yeah? I thought Australia had some weird shit going on there. Did my survival training in the outback. Sure didn't prepare me for this," Tillman responded.

"Well, this must be Space Australia."

Half an hour of marching, and no ominous rumbling beneath their feet - it looked like they were in the clear, and the colony pods were just ahead. It was eerily silent, seeing all these new homes that had just been settled in but were completely empty. "Split up and look for the communications hub," McKinley ordered. They fanned out, each searching a pod on their own.

Shepard found a supply pod, mostly with food stockpiles and a little medigel. He activated one, feeding it into his armour, which distributed it across his bruised body. He immediately felt better, and grabbed several more packets for the other marines. Over the radio, he heard some comm chatter. Someone had found the comm hub already. He was about to rejoin the group when a small movement distracted him.

Something fell on the other side of the room- a food canister. Shepard pulled out his shotgun and set his barriers to full. "Hold on, guys. I think I found something," he whispered over the radio. Paranoia, maybe. Probably just a scared colonist hiding in the corner. "Come on out. I'm an alliance marine. We're the rescue party."

What popped out wasn't even human. For eyes, flat-faced, and lightly armoured. Batarian raider. They opened fire first. Thankfully, they were using an older tech assault rifle, with the integrated cooling system. Good for raiders, and even some civilians, who usually only had one gun and no exosuit powered armour. The upside was low maintenance and nearly unlimited ammo- a cheap lead brick that needed replacing once every few years or so. It also meant a much lower maximum output- more than enough for civilians hunting a few wild varren, or raiders assaulting unarmed civilians. Not nearly enough to take down an armoured, shielded marine.

Two shots from Shepard's shotgun tore through the batarian's shields and armor, leaving the raider gasping in a puddle of his yellow-green blood. The batarian wouldn't be telling him anything. The heatclip-based weapons were designed for high damage output in a very short time- in fact, one shot probably would have been overkill already. Shepard's barriers hadn't even been depleted- they regenerated within a few seconds.

Raiders AND a thresher maw? Shepard couldn't believe their bad luck. Then again, it could have been read as poor foresight instead. Of course the thresher maw couldn't have taken out all the colonists. The pods are still intact. It would have feasted on them, Shepard reminded himself. The team had been far too focused on their recent tragedy to account for the fact that something else could have been there. And that something was a group of batarian raiders.

"Everyone, on guard and regroup! Batarian raiders in the colony pods!" Shepard shouted.

"…under fire!" came a crackling, unclear response. He couldn't tell who it was. An explosion shook the supply pod he was in. Racing outside, he saw a thick plume of smoke coming from the neighbouring pod. Must have been the fuel storage station. Three dead batarians lay on the ground- along with one dead marine. One of them must have been stupid enough to open fire in there. The charring of the bodies told Shepard there wasn't anything he could do for them.

Out of another pod came McKinley, firing his assault rifle into the pod with one hand and dragging Tillman out with him as he backed out. He looked unsteady on his feet- Shepard raced over and helped support him with extra covering fire and extraction. He noticed McKinley was forcing himself to hyperventilate.

"Nitrogen trap," he coughed out. "Damn stupid biology." Shepard nodded, having seen this happen by accident on starships before. Humans needed oxygen or they passed out. Simple enough. The human urge to breathe, or sense of asphyxiation, was based not on low oxygen levels, but high carbon dioxide levels. As long as a human was getting rid of his carbon dioxide, he wouldn't realize he wasn't breathing in oxygen. Turians, thankfully, didn't figure out this flaw until after the end of the First Contact War, but pirates and slavers were happy to pounce on it. "We have to get back in there. That's the comm relay," he said.

"I'll flush them out," Shepard said, activating his armour's internal oxygen supply. It wasn't a true spacesuit, and only had several minutes' supply, unfortunately. That just meant he had to work fast. The second the door opened, he pulled the trigger. Boom, one raider dead. He rounded the corner- two booms from his shotgun, and another raider down. Heat clip swapped. One raider tried to hide behind a couch, of all things. Boom, the shotgun tore through the lightweight plastic frame as if it weren't even there, and a splatter of yellow decorated the wall behind it. The last one had figured out that the comm relay was important, and placed it between himself and Shepard.

He couldn't risk destroying his only means of contacting help, and the shotgun was a little too destructive. His fists- or, more specifically, the biotic implants in his hands, were much more suitable. He ran towards the raider. He shrugged off the first burst of gunfire, letting the barriers do their work. A concentrated warp effect in front of his knuckles ripped through the shields. His fist suddenly weighed two hundred kilos when it connected. The batarian went flying into the back wall.

After one more sweep to ensure the room was clear, Shepard located the two other marines in the room, and tried to activate their suits' oxygen supplies. It was too late- they'd been without oxygen for too long, and suffered brain death already. All he could do was log into the pod's environmental controls and open all the doors before his own suit's oxygen supply gave out. He threw out the nitrogen canisters that were displacing the normal atmosphere in the room, and walked back outside.

McKinley wasn't responding. He and Tillman were dead. Sniper shots, straight to the head. Given the angle of the blood splatter on both of them, the sniper was obviously up on the cliffs to the west. He caught a glimpse of the sniper's movement, trying to hide behind rocks. Tillman hadn't even gotten up- the sniper had put a bullet into the head of an unconscious man on the ground. Honour was the last thing to expect on a battlefield- but the lack of it still angered Shepard nonetheless.

Now the sniper had spotted him- and he was the last one. The short-range SMG and shotgun versus a sniper rifle with two hundred meters between them. Grabbing McKinley's assault rifle would mean running out into the open- and if it had even a half-decent auto-targeting system, one round would find itself buried inside his helmet. He needed to close the distance. He wondered if he could do it again, with half his biotic amps were shorted out. No time to wonder. There really weren't any other options. Capacitors were at full. He was a vanguard without allies left to protect. Shepard charged.

Codex Entry: Thermal Clip Systems

The micro-scale mass accelerators on small arms were considered a perfected technology several hundred years ago, and little was done to increase their output until the Krogan Rebellions. While a small, integrated heatsink formed a compact, self-sufficient weapon that could last for years with minimal maintenance, massive increases in damage output were required to kill an armoured krogan.

A krogan soldier's combination of naturally redundant nervous and circulatory systems, an exceptionally rapid cellular regeneration rate, the ability to wear heavier armour and larger shield generators, proved that it was possible for krogan infantry to regenerate shields and heal minor wounds faster than a standard assault rifle could injure them under sustained, continuous fire. The only solution was a massive increase in damage output, with a corresponding increase in heat output.

Most soldiers in the armies of Citadel species tend to carry multiple weapons to handle a variety of situations. Correspondingly large heatsinks on each of them proved to be too much of a weight burden for each soldier. The Turian weapons development agency developed the Thermal Clip system, which utilizes a common heatsink cooling system integrated into a powered armour pack, with a shared, compact, universal heatsink that can be used by all military weapons.

The high damage output of thermal-clip based weapons was deemed illegal for civilian licenses, and the need for an armour-integrated cooling pack was too expensive and complex for most civilians. Integrated venting remains the system of choice for hobbyists and sport hunters.

Author's Chapter End Notes:

- my explanation for why Shepard is the one who invented the Vanguard biotic charge: we don't see it from any other character in the entire universe except one (excluding the multiplayer component of ME3). That one character being an asari spectre means she's a pretty damn talented biotic as it is, and could have easily learned it by reading reports on Shepard.

- Basic plothole of the game: yes, heatclips were invented so that players could have ammo in ME2. I have no problem with that. The problem is that somehow, within two years, one new technology is invented and everyone, from the most powerful militaries in the galaxy to the poorest gangsters on Omega to aliens living at the center of the galaxy controlled by reapers are using them. Not a huge change, but i just pushed their invention ahead a few hundred years, plus explain why any military would favour a limited-ammo system over an unlimited-ammo one.