Humanity's Greatest Mecha Warrior System

With their gas masks on and the rebreathers active, the Infantry forces slowly advanced their way through the smaller tunnels of the mountain complex.

Made of limestone, and naturally formed over thousands of years of runoff, these caverns were an amazing testament to the natural powers of running water. Or at least they were before the Klem arrived.

The monstrous insects' presence was everywhere here, and unmistakable, as their sharp legs made distinct patterns in the soft stone, and they carved away large portions of the existing tunnel walls to make way for themselves, not worried or not understanding that their cleared path only made it easier for the humans to follow them.

"Pan right, I see claw marks headed up the wall." Lieutenant Calda barked at his squad.

The claw marks were unmistakable, but they didn't seem to lead anywhere, only into the darkness above them. The Lieutenant turned his spotlight upward to illuminate the roofline better than the small lights on the laser rifles could, bringing a hidden cavern entrance into view.

"Grenade out," Calda called, lobbing the fist-sized projectile with every bit of strength he could muster.

For a Kepler soldier with a Strength base primary bonus, that was much further than what an average human could manage, and the grenade bounced off the wall fifty meters away and rolled down into the cavern on the other side before exploding.

The sound of Klem shrieking as flames engulfed the room echoed through the caverns, and an enraged rush of Klem Warriors came from the tunnel mouth, racing toward the human threat, while Lasers burned holes in their chitin.

The squad had the Warriors at bay, and the bodies were beginning to plug the exit, keeping the smoke and flames from the incendiary grenade contained, until suddenly the clatter of running feet came from behind them as well.

The branch tunnel they were in was a dead end, there was no other way out than the way they came in, or possibly out of the other side of the cavern that they had just lit on fire to eliminate the Klem inside.

"Circle up, we're fighting on two fronts now." Lieutenant Calda ordered with a grim smile on his face.

They had already spent every charge from their heavy weapons dealing with a pair of Shredders they had come across a few minutes ago, and now they were boxed in by the Klem.

The Oxygen warning on his mask began to beep, notifying him that the flames in the other room had run their course, burning all of the oxygen out of the enclosed space until they could burn no more.

That was a small blessing for his men, as the Klem still needed to breathe once they were active, but his men had an air supply that would last at least another eight hours. The lack of breathable air didn't seem to be slowing the ones that were coming down the tunnels toward him though, they were simply charging over the fallen bodies of their compatriots through the six-meter-wide tunnel spur, eager to get to the fresh meat at the end.

One after another they fell, and slowly the sounds in the cavern behind the squad fell silent, leaving them to fight on only one front, with a few men watching the rear for signs of activity.

The tide of warriors stopped, leaving a pool of greenish ichor among the bodies scattered on the floor, and the Infantrymen were cautiously optimistic. They had won this engagement, and their rotation was almost over, they could head to the surface again soon.

"Move out, let's get back to fresh air and start making our way to the surface." Lieutenant Calda ordered, making a note that the final chamber hadn't been verified due to heat and lack of oxygen.

Retracing their steps was the most efficient way out, so the squad started moving back the way they came from, past the corpses, and the small lake of disgusting blood.

They were almost to the exit when the scouts froze in terror. Not one, but two Shredders stood between them and the blessed light of the surface above them, blocking the main hallway. Corpses of infantry, and Line Mecha that Lieutenant Calda recognized as their reinforcements from the second shift littered the hallway along with dozens and dozens of Klem corpses.

"Back away before they see us. We will find an alternate exit to the tunnel complex." Calda whispered, backing away from the horrific sight. But he knew that wasn't going to happen. They had explored every inch of this branch except the final chamber. There was only one way in and one way out, and it was right behind that pair of Shredders.

On the other side of the Mountain range, things looked much different. Lieutenant Johns had been leading his squad through the caverns for ten hours now and hadn't found a single sign of life. There were abundant signs that the Klem had been here, and were headed east, but after that, just nothing.

He had checked side caverns and sent men crawling through tunnels barely larger than their bodies to see if there was anything hiding on the other side, but it was empty, the entire cavern complex in his region had been abandoned.

[Johns to Company Command. Spur TXC13B confirmed clear, no signs of previous Klem activity.] He reported, making a note on the digital map.

"Lieutenant, there is light up ahead at the end of the next main tunnel." One of his scouts reported, crouching down to stay out of sight of any Klem that might still be near the source of the light.

"Move out men, if that's an unknown exit from the caverns, Command needs to know about it. The map doesn't show anything here, much less a major cavern headed east." Johns sighed, wishing there was a better way to keep the maps updated.

The satellite data was very good, at least it was when they got it. But they had been underground for half a day, where they couldn't get updates, and even their radio signals had a hard time reaching their closest allies, so they couldn't know what the Klem had been up to until they stumbled across it.

Crouched low to the floor and hugging the shadows of the wall, Lieutenant Johns crept toward the light, through a tunnel large enough that a Crusader Class Mecha could have passed by him with room to spare. No other tunnel he had seen was this large, and it was clearly not a natural formation.

"Make a note, possible Behemoth activity," Johns instructed the scout closest to him as he reached the light.

It was an exit from the caverns, atop a high ridge with a steeply sloping hill, facing east. From here he could see the Base Camp and the defensive line of Mecha that was defending it. But more importantly, he could see the smoldering corpses of two Behemoths and thousands of Klem Warriors and Shredders.

"By the Emperor. Now we know where the Klem went, and I for one am glad we weren't here before they left. Even the whole Regiment assembled would barely make a snack for that force." Lieutenant Johns sighed, then sent the signal indicating that he had reached an exit, as well as sending the update of the tunnel structure to the ships above him since he could finally see the sky again.

"Let's stop here for a break, get everyone out into the light," Johns ordered, bringing his squad forward and breathing in the relatively fresh mountain air. With all the fighting, the tunnels had turned smoky, stuffy, and suffocating, it was good to be back in the real world.

[Lieutenant Johns, proceed to base camp to reload and restock, as it is the closest accessible position to your location.] Came the order from his Commander.

"You heard the man, it's the closest accessible position," Johns ordered his troops, who could only sigh and look at the hill in front of them.

"I don't know what happened behind us, but if two hundred kilometers on foot in plain sight of an entire squad of Super Heavy Mecha are our orders, I am not going to ask to go back into those tunnels. Now finish your smoke and get moving." His Sergeant agreed, making the men chuckle.

It might take them all day, and most of tomorrow to get there, but anything was better than fighting below ground. Their only concern was the talk of the other exits not being accessible. The infantry had no way to know that the Fusion Flamers had lit a number of the tunnels on fire, or that some had collapsed due to heavy weapons. The stone of the tunnels blocked most communications, so they only knew what was relayed to them, and that was to watch for loss of oxygen as they explored the vast underground network.

[Twenty Credits says that they don't make it here before dark tomorrow.] Colonel DiFranco of the Fourth Battalion laughed, looking at the pair of five hundred-foot vertical walls bordering a raging river that was between the infantry that had been ordered their way and their final destination.

[Twenty Credits on Sunset tomorrow minus three hours.] Colonel Klinger wagered, making the rest of the Battalion Commanders laugh, and the maintenance staff around them sigh.

"I guess that means the Mercs aren't going to send a hover truck to pick them up." One of the repair technicians told his partner with a wink.

"Likely means that if we try we would make enemies of everyone who didn't win the bet as well. Just keep your binoculars at the ready, we should be able to see them almost the entire route back to camp."