Author's Notes:

Done reading this and Dusty's fight? Decide who wins right here!

“Welcome, friends, to round one. By now you’re probably wondering where your opponents are! Well, look around. Somewhere within the Arena your obstacle to victory is thinking the same thing. So keep on your guard! You never know where they might be or what they might be capable of.” There’s a pause before he adds, “Oh, and by the way. Once one of you has proven to be a clear victor, the exit will appear at the center of the battlefield. Good luck finding it! Ta!”

With Discord’s maniacal laughter ringing in his ears, Alcauto stepped cautiously through the door in front of him, into the darkness beyond. There was no strange pulling sensation, no vertigo, only that one moment he was standing alone in small room, the next in semi darkness. The door clanged shut behind him, cutting off his only ray of light and blinding him.

The first thing he noticed was the smell. Feces, mold, stagnant air and other unsavory odors burned his nostrils. It didn’t leave much, if any, to the imagination.

“Dear Celestia, it smells like my grandmother’s bathroom in here,” the bat pony groused to himself, trying not to gag.

Taking a careful step forward, Alcauto’s vision came into focus as his nocturnal eyes adjusted to his surroundings. He was in, well, a sewer. A rather narrow passageway of one. It was pleasantly cool, yet the dank walls oozed condensation and in some places outright poured water from gaping holes. The floors were all but invisible beneath a river of what he hoped was mostly water.

Alcauto nervously resettled his wings and glanced up at the ceiling. It was unpleasantly close, a myriad of pipes criss-crossing through the hall only made the space even more cramped. There wouldn’t be any flying here, even for an agile bat pony like himself. Yet, it did bring him a small comfort that he wouldn’t have to worry about his opponent getting the drop on him, so to speak.

A dim flash of light caught his attention and made his eyes glow. Moving towards the source, Alcauto realized the tunnel was riddled with fissures that either poured water or let out a faint, flickering light. Poking his head into one of these holes, Alcauto was faced with a rather odd picture; it looked like somepony had captured a thunderstorm and then placed it impossibly far away in the hole.

Looking back at his surroundings, then into the hole again, the bat pony’s mind broke a little as to how this could be possible. At that moment Alcauto could have sworn he heard another disembodied chuckle. Giving an irritated snort, he stepped away. Of course Discord would have something to do with it, he should just keep moving and watching for his opponent.

Taking a deep breath, Alcauto steeled himself and began sloshing his way through the tunnel. He didn’t have any particular direction in mind, but instinct told him to follow the flow of water. It all had to go somewhere, hopefully not anywhere worse than this.

He cursed as he banged his head on one of the low hanging pipes, then instantly froze up as the noise echoed throughout the chamber. His ears rotated as they followed the echo’s ever fainter reverberations, trying to decipher any noticeable changes. However, if there were any openings or caverns nearby, they were not revealed to him.

When silence but for the gurgle of water finally returned, Alcauto continued his trek forward. This time, however, he moved slower and more deliberately while keeping an eye focused above him.

Wading chest deep in water wasn't the safest mode of travel, but in this narrow tunnel it was much better than trying to cramp himself onto the narrow ledge. One slip could spell disaster or a big, noisy splash. Just so long as he was slow, he would be nearly undetectable.

Alcauto wasn't sure how long he slogged through the sewer, his sense of time skewed by the endless twilight. All that mattered was keeping himself alive and alert. He could almost feel his stamina ticking away. Eventually he would need to eat and sleep. The worst part was that he didn't know how long his enemy could operate without sustenance, or if they even needed to sleep.

He wondered if Discord was watching. What if he was getting impatient? Surely he wouldn't let them starve to death—he would get bored first, right? From what Alcauto knew, Discord wanted a show.

His next step plunged him forward as the ground beneath him disappeared. With an alarmed cry he was pulled down the tunnel as if falling vertically off a cliff. He was dumped under the flow of water which had become a freefall. It was almost as if gravity no longer pulled down, but sideways.

Unable to right himself, Alcauto did his best to maintain air in his lungs and not panic. It wasn't long before he was flung from the tunnel and into open air. As he spun, he noticed he was now in a large cavern, still as gloomily lit as the tunnel. What he assumed was below him was a large pool of water. Above him, a domed ceiling that disappeared into blackness.

There were fissures and openings everywhere, many pouring water just like the one he came from, yet others that were higher and silent. Everywhere, the little holes filled with distant lights flickered restlessly. The constricting pipes which ran along the tunnel now criss-crossed around the cavern in an intricate quagmire, effectively limiting any fliers to a few hoof lengths from the ground.

The gravity changed again before he could react, throwing him into the large pool. Fortunately, the waterfalls dumping into the cavern concealed his splash with their own spray and echoing chimes.

Somehow finding his way to the surface, Alcauto took a few gasping breaths as he swam to shore. It was a sorry looking bat pony indeed that finally crawled its way onto the cold concrete ledges surrounding the pool.

He lay, exhausted from his trek and plunge, not caring who found him. Alcauto could feel his hooves pruning; which, he decided, was better than him being unable to feel his wings at all. It took a few tries, but eventually he was able to work the life back into his soaked and freezing appendages.

Struggling to his hooves, he quickly located himself a corner to disappear into while he worked his limbs back into service. As he rubbed his legs with his forehooves, he glanced about the cavern, watching for any signs of movement beyond the waterfalls.

To his surprise, it wasn't long before he did catch some movement from one of the tunnels. It seemed his opponent could fly and had adapted to the gravity changes much better than he had. As it gracefully fluttered out of the tunnel entrance and across the pool, he realized it was a changeling.

It didn't make for Alcauto, however, and the bat pony quietly got to his hooves to pursue his opponent. He didn't make it five steps before the lighting dimmed and he lost sight of his quarry. When the light finally returned, the changeling was gone.

Making his way around the pool to where he guessed the changeling would have landed, he began searching for any signs of its passing. There were wet hoofprints, but only in a small area, merely confirming that his quarry had touched down for just a moment.

Alcauto glanced up; there wasn't much space to fly. He hadn't gotten a good read on the changeling's size, but if they were good, then a small and agile flyer could probably navigate the piping network without too much trouble.

Alcauto paused as the air suddenly change its flow, bringing with it a cold whiff of mold and other unknown smells. He stood silently for a moment, twitching his nose and trying to catch any scent of his opponent.

The only problem was that he didn't know what a changeling smelled like in the first place. What if they changed odors when they changed disguises? That would certainly be a problem. Alcauto continued testing the air, hoping to pick apart what his senses were receiving.

A sudden rustle and low growl made Alcuato flinch backwards. It was a good thing as suddenly he was headbutted in the chest and sent reeling. Something dark flashed across his vision, barely discernable from his surroundings. He was pretty sure that his changeling enemy had just tried to gore him on its horn.

Quickly gathering his legs underneath him he scrambled to his hooves and faced where the something had gone. Peering into the darkness, Alcauto could barely make out the shape of a pony moving. If it wasn't for the muffled clack of hooves and the scraping of chitinous armor, he might have missed the changeling.

As it was, he was ready this time. Already Alcauto was crouching low as he took stock of his opponent. He wasn't as large as the bat pony, but had already proven he could be silent enough to avoid detection, even by a night guard.

One of the lights in the wall chose that moment to flash a little brighter, enough to illuminate both ponies. The changeling's eyes latched onto Alcauto, hypnotizing the bat pony as light reflected off its compound orbs. They stared at each other, Alcauto well aware of what his opponent had just tried to do.

The changeling bared its fangs and gave a feral hiss. Alcauto stepped backwards into a crouch, narrowing his eyes and flattening his ears. If the changeling wanted to fight, then by the goddesses he would get one.

They began to circle, the changeling looking for an opening while Alcauto keeping his front forward. The bat pony maintained a wary eye on his enemy's hoofwork, hoping for a chance to catch him off balance. He wasn't too keen on initiating any fight, not until he had a better idea of what the changeling could or could not do. But, frustratingly, he wasn't sure waiting too long was the right choice either.

Distracted with trying to remember anything he could about changelings, Alcauto almost missed his opponent lunging. He scrambled backwards, trying to put distance between them as he flared his wings to carry him to safety.

He pumped once, flinging himself backwards. As he prepared another stroke, this time to power forward and above the changeling, he was suddenly flung to the side as gravity inexplicably changed.

Tumbling hooves over hocks, he caught a glimpse of a rapidly approaching wall, which was now his floor, and a changeling in hot pursuit. Alcauto flailed helplessly, trying to catch air with his wings and slow his sideways decent.

The large cavern suddenly seemed to be much smaller than the bat pony originally thought. Working frantically to right his wings, Alcauto was finally able to pull out of his plunge. Yet, when he swooped around within yards of becoming a smear on the wall, he left the pocket of horizontal gravity and fell back into a normal, vertical pull.

Thankfully, his wing was outstretched and came to no harm as he was suddenly slammed onto his flank and skid ten feet as the momentum from his fall wore off.

Alcauto groaned as he pulled himself up. Glancing frantically behind, he found the changeling barreling towards him. He flung himself to the side to avoid being gored once again.

Finally able to catch his balance, Alcauto pumped his damp wings and closed with the changeling. Using his momentum, he powered a hoof straight at his opponent, who in turn tried to block the punch.

The bat pony was surprised when his blow barreled the changeling head over hooves and up against the wall. His shock was short lived, however, as he pressed his advantage and pounced on his opponent.

They scuffled, the changeling hissing and kicking while Alcauto tried to lock the other down. The changeling fought viciously, but it became clear that the bat pony was the stronger and more capable fighter. With that fresh knowledge in his mind, the night guard pressed his advantage while blocking or turning away any attempts of his enemy.

When Alcauto finally got a hoof around the changeling's neck, it instantly bit down on his foreleg. Unwilling to let go, Alcauto growled and lowered his own canines to the changeling's neck. His teeth grated along the chitinous armor, finding nothing to sink into. But when he twisted to get at the changeling's softer underside, it instantly let go of Alcauto and bucked, throwing the bat pony off.

As Alcauto sprang back to his hooves, the changeling darted off into the darkness. The night guard almost gave pursuit, but decided against it. He leaned heavily against the wall and took a deep breath.

He glanced at his foreleg where the changeling had bit him. Alcauto didn't know enough about changelings to know if their bite was poisonous, but the changeling running away so suddenly made him suspicious.

Sitting down, Alcauto tried to clean the wound in the pool before bringing it to his mouth and sucking. It might not be the perfect method, but hopefully if there was any venom, he would be able to get most of it out. Trying not to think of what was in the water he used, he continued sucking out blood and spitting it into the pool for the next minute.

By the time he was finished, his breathing had evened out and the adrenaline had eked from his body. The bite wound had already closed; Alcauto felt lucky the changeling hadn't thought to tear his skin. Feeling exhausted, he rose to his hooves and turned his eyes in the direction his enemy had run.

The changeling had no qualms about killing the bat pony, it had proven that when it tried to spear Alcauto with its horn. It also had enough skill to avoid detection by him, which made the Night Guard hesitant to give chase. He had never been outclassed in his own element. It grated on his confidence and nerves.

Taking to the air, Alcauto began to carefully fly through the cavern. He discovered that, in this room, the pipes were large and far apart enough that he could land on and fly in between them. It would definitely be worth making sure he always knew how to reach this central chamber.

As he followed his quarry's path, he noticed the few strange smells from earlier lingering in the air. They led him into a large passageway that, surprisingly, had no water running through it. As he glided along silently, he cataloged the smell as being related to changelings. He wouldn't be caught off guard a second time.

Another chamber loomed in front of the bat pony and he quickly recoiled back into the large tunnel. He didn't know if the changeling was watching the tunnel or not, or even if it could see with those eyes it had. Simply waltzing into another room didn't seem like a smart idea.

Yet, he couldn't think of very many alternatives. There was no telling if any of the other passages would lead to this room, if that was what it was. Alcauto frowned and glanced around. Looking up he noticed there were still a few very large pipes that were running straight into the room ahead.

Grinning, he flew up to one and landed with a soft thud. He inched forward, peering into the gloom for any sign of his opponent. The changeling's odor had disappeared, but that didn't bother Alcauto. If anything it made him feel safer; the changeling hadn't thought to come up here at all, which meant it probably didn't realize Alcauto could.

About a quarter of the way into the room, his pipe veered upwards and disappeared into the ceiling. Alcauto settled down at the edge and began to scan the room. It was difficult to see all the corners, but if he waited long enough, one of the wall lights would flare and give him a better view.

He sat quietly, double checking the darkest corners when the wall lights glowed. His eyes flashed as they swept the room. Night vision was useful, but it did have a few drawbacks. Alcauto was well aware that his eyes shone in the dark, but there was little he could do about it.

Contrary to popular belief, he did require some light to actually see; it was still really dark even in this cesspool. Many ponies thought that a bat pony's ability to see in the dark was magical, but it wasn't. Well, maybe a little, but every bat pony learned that their eyes merely worked better than other races. Which meant that if there wasn't any light, even he wouldn't be able to see.

Continuing to scan the room, Alcauto took his time. It was better to be safe than sorry. Eventually his patience paid off, as he peered into a darker corner he noticed something move! His eyes quickly adjusted and he was able to discern his changeling opponent. It was sitting on one of the smaller, lower pipes; an easy position to tackle anypony coming through the passage.

Unfortunately, the changeling was nearer the entrance than he had thought, clearly waiting for the bat pony. Alcauto was glad he had been cautious with his own entrance. He'd had enough of being surprised already.

The changeling shuffled again, prompting Alcauto to make his move. He didn't want the changeling to decide the bat pony wasn't coming and leave. Standing carefully, Alcauto spread his wings and glided straight for the changeling. Doing his best to remain silent, Alcauto didn’t even flap his wings for more speed as he dived.

He didn’t know if the changeling heard him or simply felt as though something was up. But as soon as Alcauto rotated his hind legs forward for a kick, the changeling suddenly sat up and turned around. At least, it tried to; Alcauto was too close to miss.

Still the blow didn’t strike the changeling as squarely as he’d hoped. It knocked the changeling clear of the pipe, but it was still able to recover quickly enough to keep from crashing to the floor. Righting itself, it took off towards Alcauto with a vengeance.

Alcauto swung around with a curse and divebombed the changeling. It tried to dodge, but Alcauto adjusted at the last second and tackled his opponent. They tumbled to the floor, the bat pony losing his grip as they hit. Immediately the changeling took to the air and sped away, Alcauto hot on his hooves.

He quickly gained on his opponent, although following every evasive maneuver was difficult. Alcauto had to give it to the changeling, they were certainly more agile than pegasi, but those flimsy wings really cut down on how much speed they could achieve. At least, that was his conclusion.

It wasn’t long before Alcauto was on the changeling’s heels. Putting on a burst of speed, Alcauto moved in to grab his target. But, before he could lay hooves on the changeling, it slowed, ramming itself into the bat pony and throwing them both to the floor.

The fall wasn’t far, which worked in Alcauto’s favor since he was on the bottom. He wasn’t even winded when they hit, the changeling being significantly smaller than himself. They struggled for a moment, Alcauto trying to maintain his grip on the changeling without getting bit; a rather difficult task in the semi-dark.

A green light flared brightly, almost blinding Alcauto. He shoved the changeling off, realizing it’s horn had lit up at the same time a green glow surrounded the bat pony. His opponent leapt away, trying to push Alcauto back with his magic.

Realizing he’d just let the changeling loose, Alcauto tried to pounce back on his enemy. His limbs felt as though they were in a thick sludge as he powered forward in slow motion against the magic. The changeling stepped backwards, beginning to shake and sweat heavily as it maintained its spell.

Alcauto growled and flattened his ears as he pushed forward. His lips pulled back in a snarl, revealing a smaller version of fangs similar to his opponent. He made it two steps before the changeling’s horn spluttered and went dark. The resistance pushing against the bat pony dissipated and he stumbled forward onto his nose.

A halo of light danced in Alcauto’s vision from the magical afterglow as he scrambled to his hooves, peering around for the changeling. He cursed under his breath, it seemed the changeling had bailed again.

“Get your sorry flank back here, you half-assed insect!” Alcauto shouted. He pounded his front hooves in frustration before galloping out of the room and back into the main chamber.

Nothing but silence greeted the bat pony as he skid to a halt at the edge of the large pool of water. Snorting, he turned and trotted back down the passage he had just come from. He explored the room and found there were two other exits that the changeling could have taken. Alcauto sighed and continued his trek. It was going to be an even longer, dark day.

Passage after passage, room after room greeted the bat pony as he searched for his quarry. If he had been down in a place like this for a tour, it probably would have been really cool. But now, the endless hallways filled with fast flowing refuse grated on his senses and nerves.

A number of times he encountered large chambers with central pools like the first he had been in, but it was now beyond him if he was going in circles or continually finding more rooms. The only constants were the dripping water and dark. Every so often one of the wall lights would flicker a little stronger, but the impenetrable gloom always returned shortly after.

Then there were the weird changes in gravity spliced throughout the entire cesspool. Alcauto almost hit the roof of a larger chamber when he wandered randomly into one. One moment his hooves were planted firmly on the floor below him, the next he was falling upside down as physics toyed with his mind.

It terrified him at first, thinking that the changeling had set up some elaborate magical trap. But when he righted himself and touched down on the ceiling, he noticed there was a slight tint of color that was definitely not the green of changeling magic. It was more of a purplish blue, although hard to tell with what little light there was.

A few steps across the ceiling and gravity reasserted itself, making the bat pony flail comically as he spun around before snapping his wings open and gliding back to the floor. After that, Alcauto was careful to watch for any signs of foul play by the world. Once he realized what was happening, it was easy to watch for signs. Water falling the wrong way, a weird tint of color in the air and, oddly, a tang of cotton candy.

Every so often Alcauto would catch a whiff of the changeling, but it always dissipated or became confused with something else. He wished he could pick up what he smelled like, perhaps then it would be easier to tell where he had been or not. The changes in gravity didn’t help either, continually shifting on him and changing the flow of air.

Now and again he would hear a bang, a creaking of pipes or some other sound he couldn’t place. The cesspool seemed alive, yet he never met another living being. If he didn’t keep running into a scent now and again, he would have suspected his enemy had escaped somehow.

The darkness dragged on him. He may have been nocturnal, but living in an Equestria where you could always look up and see the moon at night was much different than this perpetual black. It played tricks on his mind, whispered doubts to his ears. Each new sound made him stop, if not jump. He felt as though his fur was continually sticking straight out with a prickling sense of unease.

A loud bang ripped Alcauto from his senseless wandering. He swiveled his head to where the noise came from. It had been really loud for ambiance. Another resounding clang confirmed his suspicion. He silently began gliding towards the echo’s origin when a third bang resounded through the tunnels. It was then followed by a loud clang rattling out, almost as if somepony had dropped a large bar of metal on the floor.

Alcauto had the location now; his changeling counterpart was up to something. He needed to be quick, as whatever his opponent was up to, he didn’t want them to be ready when he got there. The passage he was in opened up into another large cavern. Taking a guess, Alcauto decided to check the far end of the room first as the echos didn’t seem loud enough to be on this side of the large pool.

He took a running leap and began to glide silently across the black water. When he reached the far wall it rose up to a ledge about twenty pony lengths straight from the water’s edge. Alcauto flapped carefully and silently upwards and landed. To his right was a corridor that stretched as far as he could see, to his left was a large opening he couldn’t see around.

Creeping slowly to keep his hooves from making any noise, Alcauto peered around the corner of the opening. Nothing. He stepped forward into the opening and his eyes fell on a pile of loose mortar. There was also a broken piece of pipe, its shiny end confirmed that it had just been shorn off. Whatever the changeling was up to, he had just been here.

Alcauto nudged the pile of rubble, scattering it as he snooped around. A green glow erupted in front of him in the darkness, the changeling pouncing forward and swinging something encased in its magic. The bat pony ducked just in time to hear the air whistling through a section of piping before it crashed into the wall next to him.

He pounced forward and tackled the changeling. A clang echoed from behind them as his opponent’s magic sputtered out as they hit the floor. In an instant the changeling had bucked hard, shoving Alcauto off over its head.

Landing gracefully on his hooves and ignoring the pain in his ribs, Alcauto charged again. This time he lashed out with both forehooves and sent the changeling cartwheeling backwards with a satisfying thud.

Continuing his assault, Alcauto made to pounce the changeling again. But before his opponent even finished landing, his horn was glowing again. Halfway through his jump, Alcauto felt something slug him in the back of his head.

His vision filled with stars, and instead of dealing another decisive blow he slammed meatily into the changeling and they both toppled over the ledge. Alcauto experienced a couple seconds of terrifying freefall before he hit the water with the changeling under him.

The stars faded into blackness, but in his semi conscious state Alcauto couldn’t understand why he couldn’t see anything. Had the changeling hit him that hard, did his eyeballs fall out? It took him a few more seconds to realize he was underwater and couldn’t breathe. Panicking, he began swimming in what he desperately hoped was an upwards direction.

His lungs screamed; he hadn’t taken a fresh gulp of air before hitting the water. The next few seconds seemed the longest he could ever remember seconds being. Alcauto broke the water’s surface and flailed, taking great gulps of air as he floundered.

Blinking, Alcauto peered about, his nerves calming as his vision returned. It seemed there was a current in the pool and it was pulling him away from the ledge. He began swimming for one of the edges. His head rang and his neck was on fire. He felt nauseous. The strokes became harder and his breathing ragged. Just when he was starting to panic again, his hoof suddenly struck stone.

Breathing a sigh of relief, Alcauto heaved himself up and collapsed on the floor only halfway out of the water. He laid there for a moment before he became aware of another pony thrashing around in the water. Pulling himself up with a groan, Alcauto rolled over and looked back out over the pool.

The changeling looked to be having a hard time swimming to shore, but it was slowly making its way to a spot not far from Alcauto. Heaving himself upright, the bat pony moved to intercept. He waited quietly as the exhausted shapeshifter dog paddled to shore. It grabbed the side and then hung there, not even trying to pull itself out as it panted, oblivious to everything around it.

Alcauto stepped forward and grabbed the nape of the changeling’s neck in his teeth and heaved. The changeling popped out of the water with a surprised yelp before it was slammed down onto the hard floor with a crunch.

To Alcauto’s surprise, the changeling lashed out immediately, catching the bat pony on the muzzle. He reeled backwards, clutching his nose as blood fountained from it. Alcauto lashed out with a blind buck and hit something with a satisfying thunk.

Taking a moment to compose himself and wipe away the blood, Alcauto turned and searched for his opponent. The changeling was picking itself up off the floor, shaking away the aftereffects of the bat pony’s buck. They charged each other and locked hooves.

They hissed and growled, striking out with hooves and teeth. Alcauto shoved the changeling into a wall, who then in turn swept his hooves out from underneath him. As the bat pony went down, his teeth connected with one of the changeling’s wings and tore it wide open.

The changeling screamed and staggered away as Alcauto jumped back to his hooves. He rushed his enemy, but almost took a hoof to the face as the changeling turned and swung a hoof at him. Dodging just in time, Alcauto stumbled around the changeling as it hissed ferally and tackled him.

Alcauto finally found an opening and kicked the changeling back against a wall. They both stood panting and eyeing each other. Neither growled or hissed at the other, their breath no longer worth wasting on intimidation.

With a grunt, the changeling charged straight for the bat pony. It was almost too easy for him to sidestep and deliver a crushing buck to its side. A sickening crunch echoed through the chamber as it connected with the changeling. It collapsed to the ground in a heap, flailing limply.

Moving forward, Alcauto cautiously peered down at the immobile changeling. It was panting weakly and its eyes narrowed at the bat pony’s approach. Yet, when it tried to stand, it merely flopped limply and whimpered.

Alcauto narrowed his eyes. “It’s over.”

They looked at each other for a long moment, neither moving. The fight wasn’t over, but Alcauto wasn’t sure he could end it like this. He turned away and peered into the blackness around him.

Now what?

Before he could ponder what to do, the changeling tackled him from behind. Alcauto stumbled, but remained on his hooves as it clutched his back. The bat pony instinctively reached up behind him and grabbed the changeling.

He pulled hard, wrenching the weak changeling forward and flinging it to the ground in front of him. Without thinking, Alcauto raised a hoof and brought it crashing down on its exposed neck. There was a meaty crunch as his hoof broke through cartilage and crushed the changeling’s windpipe.

Alcauto stood, transfixed, as the life bled out of the gurgling creature. It took longer than he thought it would, and he watched every agonizing second of it. When he finally stumbled away, he still saw the eyes of his opponent slowly clouding over.

“Once one of you has proven to be a clear victor, the exit will appear at the center of the battlefield.”

Barely thinking or seeing, Alcauto made his way to the center of the arena with Discord’s instructions ringing in his mind. It probably took longer than it should have, but eventually a glowing door revealed itself before him. Standing up straight, Alcauto marched through the exit and into the world beyond.