Her progress slowed the closer she got to reintegrating with the greater tunnel. Assuming the pack behavior applied, the Aud would attract their own. They'd gather in places where a sizable population already existed. Her suit creaked like it was voicing agreement.

  She'd waited ten minutes for her surviving drones to reach her. Then she'd had to double back or make a new path for herself several times. Her HUD had improved at identifying weaker walls, but the WAV couldn't continue like that much longer. It was a scouting vehicle, for crying out loud! Not a tunnel boring machine!

  Never mind that she knew the drones would outlast her. Pa-5 didn't like it. The sitesman should've stored the data on a hundred drones, sent them instead of the suicide runners. She was already shaking her head at the ridiculous idea.

  Drones couldn't reserve the space for the right-sized microchips. They'd need that for a long-lasting battery and a long-range communication module to make the trip possible. If she were on the development project for the drones, what design choice would she've taken?

  Those who had enhanced the machines' endurance over their versatility. She couldn't blame them. Confronting beasts that were so hard to kill had become the regular pastime of the military. It made efficiency and endurance the foremost concern in the conflict.

  Her current tunnel was clear, drawing a sigh of relief. Pa-5 took a moment to herself to still the tremors. How long had it been since the earliest injections? What she prepared to do if it wasn't wouldn't have been pretty. She'd rather conserve the limited explosives she had left.

  The HUD alerted her. "Notice: Purple fur detected. Estimation: Twenty-eight percent chance of Aud present within forty-five meters. Advisory: Proceed after assessing individual case and willingness to risk life."

  "Thanks."

  A less than forty percent scenario was good enough for her. She didn't have the time to continue making detours in the hope of finding a guaranteed safe path. She stopped by the mouth of her most recent detour, breathing deeply. Why couldn't the suit inject more hormones without the adverse side effects? She took another drink to ease her nerves.

  Jumping onto a ledge, she crept along the path. It was good that the higher crawling space continued until the tertiary checkpoint. No Aud would be small enough to get her up here.

  That didn't mean much. All it'd take to bring her down would be another cave-in. A purple Aud, rare as they were, was the apex of what the damned things could become. It was in part due to their rarity that she felt secure enough to make this choice in the first place. That, and her time constraints.

  She had to question how hopeless her actions were as she swung across a gap in the ledge's path. It was completely unknown what the Aud would do next. Would they lick the minuscule wounds they'd suffered and make a move immediately? Or would a period of relative peace settle in again?

  Pa-5 didn't know much about the oldest bastion outposts. Fort Callipso and Fort Clyvis had fallen decades before her birth.

  Callipso had been the first, a wake-up call for the Directory of the time. The previous lull in conflicts hadn't been the new status quo, just a break from the violence. And Clyvis hadn't even been fifteen years after it. Losing the guard posts for the northern and southern greater tunnel entrances had generated mass paranoia.

  There would be a reckoning, she was certain. Of what, and by whom, she wasn't able to say, but she knew something had to give. The Aud had to have limits. It wasn't like they were machines. They weren't even cyborgs.

  The rare dissected Aud had been publicly reported as nothing more than a biological mammal. Their internal organs weren't even radically different from humans.

  She missed the whispered intake of air. The HUD didn't, but it only logged the sound as an irregularity produced by the caverns. It would only bother its user with priority details of the environment. The lack of vigilance on both their parts was their first mistake.

  A crashing wave of fur and claws slammed into the back of her WAV. She flew, slamming into the opposite cave wall and falling from the ledge. Her mind was blank with panic for a few precious seconds. They felt long, so long, until--

  The ground punched her from below, knocking free what little air she'd held onto after the scream. Pa-5 struggled up. She needed to get an angle on her attacker, to prime the cylinder clenched in her palm--anything! The HUD made a whining noise but persevered through the abuse.

  "Addendum: Diagnostic: WAV suffered musculature tears. Left knee servo jammed."

  Pa-5 improvised on the spot. She turned off the suit's frontal visual feed and cracked the cylinder against the ground. She sat through two agonizing seconds. Feeling the heat from the flash grenade seep through her armor, hearing the familiar roar, didn't make her at ease just because it was familiar. No, that was a growl this time.

  She squinted, flicking visuals back on. A thud and a tremor throughout the tunnel told her her assailant had fallen from the ledge, too. She used the brief respite to retrieve another cylinder. Through teary eyes, she could see the purple, no matter how faint or blurry the silhouette.

  She couldn't let up, not for a second. She threw the next one, turning her back and limping away. Damn suit. It had worked as well as she could've wanted from it until now. But one fall, then the joints threw in the towel? She slammed her fist into the knee repeatedly, ignoring the pain in her actual joint. Come on. Come on. "Come on!"

  If you discover this narrative on Amazon, be aware that it has been stolen. Please report the violation.

  "Advisory: Secondary cave-in provides forty-nine percent chance of continued survival. Notice: Appli--Notice: Nominal degree of motion restored in left knee joint."

  How nice of it to inform her of the fruits of her painful labor. The knee would function as well as a dented and near-broken servo forced back into place could.

  The thuds at her back and the HUD blaring in her ears convinced her to roll out of the charging Aud's path. Her hand slung the next cylinder without conscious control. Another bang, another growl, and a second crash. She launched her second explosive as well.

  This tunnel was larger. The explosion covered less ground without a tighter tunnel to hem it in. Pa-5 was well clear of the impact zone when the cave-in started. The purple leaped at her, maw gaping. No way the suit would last any longer in its bite than she would.

  A chunk of the ceiling, double its size, cut the arc short and pinned it. Pa-5 didn't wait to see how long it'd hold, already on the move. She winced as she dodged a rock of her own, feeling the pinch in her chest. She would've ignored it if not for the blood she coughed up. "Blergh. HUD?"

  Painkillers, coagulating agents, and the smallest dose of liquid sun entered her bloodstream. Internal bleeding was tricky. The suit couldn't judge the severity of her injuries. It lacked the precision and power of dedicated medical equipment.

  All she could tell was that certain parts of her body hurt more than others, so she wouldn't be any help either. She shrugged, wincing at that too.

  The new and still-growing rockpile, amounting to tons of weight, didn't stop the purple for a minute. Barely ten seconds passed when a rattle reached her ears.

  She could waste precious seconds finding the right curse word or finding cover. She dove behind a growth of inverted stalactites, the thickest she could find on short notice. 'Nice to know I'm not losing my edge yet.'

  Like grapeshot, the purple's freed roar and the rubble shot outward. Each chunk slammed into the walls with enough force to pulverize a white. She crouched down, making herself as small as possible while covering her head and neck. 'Please hold,' she begged the tunnel. 'Please hold,' she pleaded with the stalactites.

  They could've been close enough to the greater tunnel that the rocks had hardened somewhat. Or the damage looked worse than it was. Whatever it was, her chosen barrier held. So did the tunnel walls and roof. She opened the leg compartment, fighting off despair as she took out the last flash cylinder.

  Fine. She'd have to make it count this time. Really make it count.

  Nothing all that scary. It was a biological murder machine that would rip her apart if it caught her. Not that scary, as far as deaths went. She could imagine worse ways to go. Burning. Drowning--though where would there be enough water for that out here? Crushing.

  Compared to all that, a quick shake of its powerful neck, and her spine would snap in its maw. That was better, wasn't it? Pa-5 decided she'd find something better for herself than self-motivational thoughts. Something had to work better. She was ready to toss when she heard something she wouldn't have expected in her wildest dreams. Footsteps. "HUD?"

  For once, the program had nothing to say. Calculations were only useful until an event with zero percent chances of happening happened. She peeked through a crack in the stalactites.

  The purple stood tall and unbeatable, as it had always been. But it wasn't looking in her direction anymore. She didn't doubt it knew exactly where she was hiding.

  No. Its undivided attention was on the silhouette marching toward it. A human silhouette. Pa-5 received another injection, its effects lost on her as she stared at the human.

  She couldn't tell the gender. Garbed head to toe in black. A body glove? And what were those shiny instruments grafted to the arms? She adjusted the optics, finding a setting that enabled her to see that far away.

  If she didn't understand before, she'd...well, she wasn't any closer to understanding. Starting halfway down the forearms, the person's limbs ended in blades. They scraped the ground, tiny sparks trailing in the darkness.

  The Aud growled. Its posture tightened. If the new optic settings weren't making it blurry enough for her to mistake it, the hackles had raised. It was taking the newcomer's presence as a challenge.

  She recognized the telltale signs of the beast preparing for a charge. But the warning she'd been willing to risk herself to call out died in her throat. They, instead of running…took a battle stance, arms held like a praying mantis.

  The Aud charged, its bulk presenting an unstoppable force. When it reached its target, the newcomer slipped around its left, blades spinning. Or were they swirling? The Aud screeched to a halt, turned around, and repeated its actions.

  Each time, the newcomer treated the intrusion into their space like a nuisance. They spun out of danger with little effort. Watching the display made Pa-5 embarrassed for her clunky, panicked dives to safety. Each movement was part of a greater dance. The blades whirled, growing in speed alongside her amazement.

  A spatter of something stole her attention. She focused on the ground, noticing strange marks. No, those were stains. From fluid. Blood? She refocused on the blades, realizing they'd been dripping in viscous purple. Aud blood! Their blades were drawing blood!

  The purple screamed again, stopping. She'd lost track of how many charges it'd initiated. It didn't matter. It was leaking blood freely now. She couldn't see the cuts beneath all the fur. It had to have felt matted down, sticky; it must've suffered a great number. Her fist clenched as the defeat of one of humanity's great monsters happened before her eyes.

  The newcomer never spoke. The only part of their body that broke the silence was their feet. They clapped and stomped and met the ground like a friend. Every second induced a new, painful-looking movement, like it was child's play.

  How many servicemen would sacrifice their lives to bring down this Aud? A hundred? No, at least hundreds, or more likely a thousand.

  Screeching in frustration, the Aud backed away from the figure at last. Pa-5 noted with interest that purple drenched their blades. Despite the proximity, not a speck of gore had touched the outfit itself. The figure stepped forward thrice for every hoof and claw trailing in reverse. That way, they prevented the distance from widening.

  Pa-5 watched as a high-tier Aud got routed for the first time in her miserable life. Not by an army, but by a one-man army. Not by the greatest technology humanity could muster, but with two simple swords. The figure kept pace with the Aud. She realized it was being herded away.

  The Aud was the first to leave the suit's visual range. Before they followed into the darkness, the silhouette turned around. Their eyes found hers.

  She became hyper-aware of a trail of sweat running down the back of her neck. The HUD enhanced the visual without her asking. Two fiery yellow orbs slipped close in her vision, the first splash of color she'd seen. Their eyes remained locked for an eternity. When she blinked, the silhouette's absence left behind yellow spots.