Author's Notes:

Before you being, I suggest that you read the prequel, Cold Harmonics, first.

If you have already, thank you and read on.

There is a place that lies beyond the watchful eyes of Equestria’s guardians. Far beneath the surface of the earth, below the tunnels of greedy diamond dogs and hives of ravenous changelings, was a world as dark as it was mysterious. Ancient shadows move with a life of their own amongst vast forests of gnarled trees. Knights in blackest armor guarded a sepulchral city and patrolled ancient roads at the behest of a silent king. Five ancient rivers flowed ceaselessly under a stygian sunless sky. One of these rivers burned like oil as it ran alongside a wide road of blackened stone. If one were to travel this highway, the darkness of the world would eventually give way to an infernal light as the destination drew closer.

At the end of the ashen road loomed a truly massive fortification. Cyclopean onyx walls stretched from the floor to the unseen ceiling far above. Runes of unknowable origin were etched into the mighty edifice, each one but a part of a single magnificent design. But there was a flaw in the otherwise perfect bulwark. Where once gates of brass and a fortified gatehouse dominated the area, now was only a blasted ruin of rubble and melted metal. Only the presence of one of the most vicious monsters ever spawned and an encampment of some of the most hardened warriors of the realm kept what skulked beyond the breach at bay but only just.

Within the walls of the primordial prison stretched miles of scorched fields. Storms of ash and cinders from raging volcanoes wracked the hellscape while a titan of flesh and metal herded hunched and wretched beings deeper into the fields with their hundreds of hands. From time to time, the warden would pick out one of its charges and incarcerate them in iron cages suspended high in the acrid air by claw-like towers. These were special cases that could not be simply shunted off with the rest of the chaff. One such damned creature was crammed into a cell a few sizes too small for him. It only served to compound the absolute loathing he felt toward those who had placed him there and the means by which they did so. He had accomplished so much and tasted ultimate power only to be thwarted by a fatal flaw.

“Why did I get cocky?” He growled to himself as he pulled his tattered cloak tighter around his thin body, his only shield from the shrieking winds and stinging embers. “I had won! I should have ground that purple pony to gristle the instant she challenged me! Then they would have never figured out how to open that infernal lock-box!”

The wretch pressed his face against the bars and glared impotently at the blasted fields. All the fuming and grumbling in hindsight could not change the fact that this was his home for the foreseeable future. His previous method of escape had been a one off and all other avenues he could think of either required power he no longer possessed or were closed off.

"I've proven that escape is possible but not permanent." The hermit sighed as he ineffectively pulled at the bars of his cell. "It is like the ultimate tease. We get to nibble on the end of the carrot before the stick beats us down like a rented mule. Truly, the cruelty of Tartarus knows no bounds."

*Ring-ring*

The light tingling of bells cut through his bout of self-pity. Suddenly, his cage lurched violently as it was reeled in closer to the wicked tower. The prisoner looked between the bars of his cell to see a small, dark blue ram waiting for him. The crimson lights of Hell glinted off the tiny golden bells the red-eyed goat was wearing around his neck and curved horns. The iron cell locked into its station and with another bell chime, it creaked open.

"Urgh! Aah, even the tiniest measure of freedom is sweet down here." The centaur grunted in relief as he stepped out onto the landing and stretched his cramped limbs. "Thanks, Grogar."

“Figured I’d find you here, Tirek.” His rescuer rasped with a somewhat friendly smile. “I take it your vengeance did not go as planned.”

“No, I just felt like coming back down here for the company.” Tirek grumbled sarcastically. "I suppose I could claim I had my vengeance but it did not stick nor did I have much time to enjoy it."

"I heard that you actually sent the Princesses down here for a bit." Grogar said candidly. "You must have come closer than any other enemy of the Alicorns."

“Oh, I was this close. This fucking close!” The crimson centaur held up a bony thumb and finger to show just how close. “I can’t believe after being stabbed in the back by that sadistic slaver and spending months lurking in the Everfree like a hermit that I would be defeated at the height of my power!”

Grogar stifled a laugh at his big red friend’s expense. Word traveled fast in Tartarus and news of the ‘mighty’ Tirek’s second defeat was the talk of the sulfur pits for a good while. Still, he knew better than to interrupt the centaur’s rant until he ran out of steam.

“I was sure I had accounted for everything!” Tirek continued to vent. “How was I supposed to know there would be four Alicorns to deal with?! Not mention a damn magical box!”

He slammed his fists into the wall and started beating his head against it in frustration.

“Now! I’m! Back! To! Square! One!” He punctuated each word with a head slam. “Ow.”

“At the very least, you got to see sunlight again.” The blue ram tried to lighten the mood to little effect. "The best I got was tree roots."

Tirek glanced at Grogar and noticed the numerous stitches crisscrossing his body. The last time he saw him, the blue ram had slipped past the Brass Gates as part of their original plan to escape the Infernal Prison. The bell-ringer was to lead the three-headed guard dog of Tartarus, Cerberus, away from his post. An escaping inmate was one of the only things that gained the normally sleepy dog’s attention as well as his wrath. It was not a great leap in logic to assume that the hellhound had caught up with the ram.

"I'm surprised there was enough of you to put back together." The withered centaur said as he rested his head against the now dented wall. "Not to mention anyone willing to do so."

"All they really salvaged was my soul. This body was...fabricated. I'd rather not say how." Grogar shivered slightly at the memory of how he had been resurrected. "As for who, lets just say there are some sick fucks down here but you already knew that."

"Demons then." Tirek assumed.

The conversation died off with that. The ram moved past the weary warlock and looked out across the hellscape. The prison tower offered a fair view of the area including an overlook of where the Brass Gates once stood.

“Hmm, the minions of the Silent King haven't fixed your little mess yet.” Grogar said as he absently played with one of his bells. “At least we still have that advantage for our next attempt.”

The hermit buried his face in his hands and let out a long sigh. The weight of ages became apparent on his thin frame. He had been plotting and scheming for years and the long series of setbacks and outright failures had gotten to him.

“Truth be told, bell-ringer, I’ve gotten sick of this for the time being.” Tirek groaned. “I’d much rather just go down to the Second Circle and get a drink or something. Maybe try my luck with a succubus.”

“*Ahem*I have to advise against that.” The ram said with an ash-filled cough.

“Do you?” The warlock arched an eyebrow at the smaller wizard. “Then by all means, enlighten me as to why I don't want to pass out balls deep in a piece of hot demonic tail."

“They do unspeakable things to you once you're out for one but that’s not the point.” Grogar answered swiftly. “Her Infernal Highness has summoned anyone who can hold a sword, cast a fireball, conjure an imp, or speak in complete sentences to Pandemonium. Needless to say, that includes us.”

Tirek’s attitude immediately went from resigned defeat to piqued curiosity. It was not often anyone was summoned to the capital city of Tartarus. Most inmates avoided it if they could and for good reason.

“Has she now?” The crimson centaur mused with a stroke of his scraggly white beard. “Do you have any idea why?”

“Well, according to rumors I've gleamed from some of the eldest demons, our little stunt has made waves down here.” Grogar whispered conspiratorially. “The only response from the powers that be were a few additional troops so many now think escape is possible en masse. Corona intends to make this a reality.”

“Hmm.” Tirek mulled over this tidbit of information and let his mind explore a few tangents. “I wonder if the destruction of the Crystal Empire has shifted the balance of power down here. Why else would she wait until now instead of right after we made out escape?”

The cataclysm that had befallen the ancient empire had been felt even down in the depths. The subsequent influx of souls deemed wicked by the powers that be all told a sordid tale of invasion, enslavement, war, and ultimately annihilation. In comparison to some of the other stories floating about the Pits, it was nothing too special but it had reached Tirek’s ears nonetheless by way of a chatty harpy.

“One could do a lot with all those souls.” Grogar nodded in agreement. “But we won’t know for sure unless we go to the Fifth Circle.”

“Very well then.” Tirek decided after a moment of thought. “Let’s see what the hot head has planned.”

The withered centaur and hunched ram descended the iron tower and exited out onto the blasted fields. Making sure not to draw any attention to themselves be it from curious shades or the patrolling titanic warden, they crept toward the volcanic crags that surrounded the massive crater that lead into the depths of Tartarus proper. The two knew that they would need all of their strength just to make the journey to the Fifth Circle. As any demon worth their horns knew, the Infernal Pits only got worse the deeper you went.

Three ponies flew far above the green canopy of the mighty Everfree Forest, two thestrals and an earth pony passenger. Under the starry vault of the night sky, Night-Captain Vengeance and her brother and co-captain Knight we returning from the Frozen North with a token of Equestria’s pyrrhic victory over the legions of marauders that had invaded and a lone survivor. With a body darker than the blackest void and white eyes than seemed to only convey baleful intent, only a fool would trust such a equine. At least, that was Vengeance’s initial impression of their passenger. During their flight, the shadow pony only known as Grey had proven to be an amicable, if somewhat odd, individual if his conversations with her and her brother were anything to go by.

“…and that’s how Princess Luna and I met.” Grey had just finished explaining how he and their nocturnal mistress had gotten acquainted.

“Lucid dreamer, huh?” Knight said with an impressed nod. “A god in your own little world.”

“That’s one way of looking at it, Night-Captain Knight.” The dark pony said evenly.

“Well, you’re in our world now.” Vengeance interjected. “And we expect you to abide by our rules. Understand?”

“Oh, perfectly.” Grey responded.

While Grey exercised his gift of gab, the gears in the ordered confines of his mind were turning. His priority was, as always, his one true home of Barathrum. Equestria and her allies in the Crystal Empire had proven most useful in providing him with the information and means to get there and he intended to get all that he could out of them before setting out. He already had a place to start: the thestral colony of Hollow Shades and the surrounding area. But he had to be cautious. If the many books he had read were to be believed, Canterlot was nothing like the Crystal Empire. Without the advantage of a siege drawing attention away from him, he would have to rely on stealth and guile to get by. Thus far, his only real ally within the capital city was Princess Luna. The late Crystal Prince-Regent Shining Armor had provided the means to at least get acquainted with the Princess of Magic, Twilight Sparkle and Princess of Love, Mi Amore Cadenza but that had drawbacks. He had survived this long by keeping the number of those who knew about him to a minimum. If his true nature and intentions were to be revealed, he could only see imprisonment or extraterrestrial banishment in his future. He had already spent an eternity exiled beyond space and time, he did not intend to return to that horrible blackness.

“Book under his bed, love and forgive.” The stygian stallion reminded himself of Armor's last requests. “Even if it doesn’t work, I owe it to Armor to fulfill his last requests.”

“Canterlot’s dead ahead.” Vengeance called out. “See the lights?”

“I do.” Grey confirmed. “Dare I ask why build a city on the side of a mountain? I thought dragons were common here.”

“It’s a symbol of the Princesses' benevolent power and to guard against ground invasion.” Knight explained as he adjusted the straps keeping the trophy helm tied to his back. “Magic protects us against aerial attacks…or it used to.”

A pointed silence fell between the trio of ponies. Magical protection was the once the responsibility of Captain Armor. With him gone, the Princesses had taken over and they would keep this responsibility until they named somepony else to take up the mantle of Captain of the Guard. The thestral stallion broke the uncomfortable silence with a cough.

“*Ahem*We’ll be landing in the gardens where Mistress Luna and her bodyguards will be waiting for you.” He said as they drew closer to the towering city.

“So don’t try anything.” The bat-pony mare warned. “You’ll be dead before you hit the ground.”

“Noted.” Grey deadpanned.

From their approach, the animus could better see the layout of the capital. The palace itself jutted out from the side of the mountain a fair distance while the actual city hugged closer to it. He could now understand the strategic positioning. One could see an approaching enemy from miles around and any ground based army would have to march up the mountain. With magic on their side, it seemed the stallions and mares that called the city home lived under the best security imaginable.

“Yet, why do I sense that there is one crucial weakness?” The shadowy pony could not shake the odd feeling. “Something about the mountain itself…”

He filed that question away for later. He was here as a guest, not a spy. He would only stick his nose in the city’s secrets if and only if it meant getting him closer to home. The bat-ponies bobbed and weaved through the towers of the palace as they came in for a landing. They touched down in the royal gardens with nary a sound. Grey dismounted Vengeance who popped her back once his weight was removed.

“You alright?” Her former passenger asked.

“I think that’s the longest you’ve ever had a stallion on your back.” Knight said jokingly. “And he didn’t even need to buy you a drink.”

“Oh, shut up!” A now furiously blushing thestral mare hissed at her brother. “And to answer your question, I’m fine. Thanks for asking.”

The two Night-Captains exchanged whispered insults as they lead him through the garden to the rendezvous point. Grey took a moment to admire the natural beauty of the plants. While his home was mostly dark and gloomy, he did learn to appreciate the little things found in nature’s bounty. After all, it was a humble narcissist that led him to his first love.

“Wonder what flowers Luna likes.” Grey thought.

His baleful eyes fell on the star-shaped blooms of a bunch of moonflowers. The nocturnal Alicorn would probably slap him for being corny but he decided to risk it. Anything that could lessen his intimidating appearance would be a boon in this situation. With the thestral’s backs to him, he formed a hoof into a pair of blades and snipped a few of the white flowers at the stems and phased them into his tenebrous body. With his gift for the Princess selected, he followed the bat-ponies into an open lawn with a large ornate statue in the center. Illuminated by the pale moon overhead, Grey could see an idealized version of the late Prince-Regent flanked by a brave Solar Guard and stalwart Crystal Guard. While the plaque was too far for him to read, he could infer that it was a monument to those lost in the destruction of the empire.

"I suppose that is one way to honor their memory." The stygian stallion thought. "No thestrals though. Bias on the part of the diurnal equines, perhaps?"

All around him, the predatory eyes and pearly fangs of the Nigh Guard glowed in the moonlight. All of them were focused on him. The three stopped short of the statue and Knight trotted toward a cloaked figure looking up at it. Grey did not need to see the horn protruding from beneath her hood or notice her royal stature to know it was Luna.

“Mistress, we have brought the stallion back from the ruins of the empire, as you requested.” Knight reported as he knelt before his matron. “I have also retried the horned helm of the Legion's warlord as a trophy.”

“Thank you, Night-Captain Knight.” Luna said as she faced her servant grasped the worn but no less imposing piece of armor in her magic. She ran a critical eye over it and knocked it a few times with a hoof before she gave it back to the thestral. “Place this in the vault with the collection.”

“As you command, your highness.” Knight replied as he flew off to do his mistress’s bidding.

The Princess watched her loyal minion disappear into the palace before turning her attention to the shadow pony. In the pale moonlight, only her muzzle and softly glowing blue eyes were visible. Grey respectfully bowed his head as the nocturnal Alicorn trotted toward him.

“At last we meet, face to face.” Luna said calmly. “I hope you had a good flight, Grey.”

“I did.” The stallion said genuinely. “Your thestrals were most accommodating.”

“I see you are just as charming in the waking world as you are in your dreams.” She said with a small smile. “Though I must admit, I expected you to look more like the pale horse I’ve come to know you by.”

“Spending eons skulking about in the deepest of shadows will do that to you.” Grey said as he held up a solid black hoof. “But it does allow me to do this.”

The living shadow produced the moonflowers from his stygian body. He offered them to the regal mare with a flourish. A murmur of suspicion ran through the assembled Night Guards including Vengeance. Luna merely held up a hoof to silence them and they obeyed. She leaned in and sniffed the delicate petals.

“They’re lovely.” She said gently. “Fresh from the garden behind you, correct?”

“I didn't know if they were for decoration or consumption." The teneborus traveler admitted. "I took a risk."

The Princess bit off the flowers at the stems and chewed contently. Once she had finished, she smiled genuinely at the austere animus.

“You chose correctly, Grey. They were delectable.” She motioned for her bodyguards to move as she turned and trotted back toward the looming palace. “Now come, we have much to discuss.”

The two trotted side by side flanked by the still wary thestrals. As they crossed the threshold into the palace itself, Luna flipped her hood back with a toss of her head, allowing her starry mane to flow freely. With her face now visible, Grey could tell by the dark circles under her blue eyes that the nocturnal Alicorn was tired.

“Likely from dealing with the fallout from the destruction of the Crystal Empire.” He surmised as his wandering eyes ran over her impressive figure. "Even still, a vision of beauty if I ever saw one."

“I know you still aim to return to your old home.” Luna said, cutting through his thoughts. “But I hope that after spending some time here, you might consider making your stay more permanent.”

“Anything could happen.” Grey said casually. “Though I’m not sure everypony here would welcome the likes of me, particularly your sister.”

“You may be surprised.” The Lunar Princess responded a little defensively. “She was willing to give Discord a second chance and you’ve already proven to be a fine ally to Equestria.”

“Princess, you flatter me.” The shadow stallion said lightly. “Perhaps when she is unoccupied with her duties, I’ll make my presence known.”

“Tomorrow morning, before the day court begins, would be best.” Luna suggested. “If you want, I can introduce you to her.”

“That may be best. I have yet to meet a pony that hasn’t threatened me or outright attacked me upon first meeting.” Grey gave Luna a knowing look that made her blush.

The two continued their way through the palace. With the exception of Luna and her thestral's hooves striking the floor, it was eerily silent. In time, they came to a long corridor filled with ornate doors. Luna signaled a guard to open one of them. Inside was a luxurious room with a king sized bed, mahogany desk, and a spectacular view of western Equestria via a large bay window. The Princess gestured for Grey to enter.

“These will be your quarters for the time being.” She explained. “As far as the wait staff is concerned, you are a solitary Merchant Prince from the Mareiterranian here to negotiate a trade agreement with the nobility.”

“Better than a hospital bed.” The ancient apparition thought. “I’m moving up in the world.”

“Does this Merchant Prince have a name or am I still 'Grey'?” He asked.

"There is a saying among them: 'Names are for friends so we do not need any.'" The Night Princess explained. "Most simply go by the title followed by the name of their city-state. They only reveal their true names to those they trust deeply and intimately."

"A name does carry power." The Lord of Shades mused. "Such was the case with my siblings and I."

"Fascinating." Grey said earnestly. "You have my thanks, Princess Luna."

“You’re quite welcome.” The Alicorn of the Night nodded once. “I would love to stay and talk but I have duties to attend to.”

“Then I won’t keep you.” The stallion bid farewell to the Alicorn. “Have a pleasant night.”

“May you as well, Merchant Prince Grey.” Luna said with a sly smile. “Welcome to Canterlot.”

With that, the navy Alicorn exited the room, the steady clip clop of her hooves fading away along with those of her bodyguards. Once he was sure they were far enough away, the shadow pony morphed into a more familiar form. His bottom half collapsed into a nebulous black fog while his fore legs shifted into long arms with bladed talons for hands. The equine features of his head melted away until he resembled a tall biped clad in hooded black robes of shifting darkness. The Lurker, the voidian shadow fiend of the Frozen North, silently floated toward the window and looked out at the magical land beyond. He could make out a quaint little village dominated by a towering tree shaped castle a short distance away from the base of the mountain. Just above the settlement floated a pegasi cloud city, its cascading rainbows nigh invisible against the night sky. The tenebrous terror looked beyond both of them to the expansive Everfree Forest.

“Somewhere out there is Avernus; the first step to Barathrum and the Immortal Throne.” He thought. “I WILL reclaim what is mine and woes betide anything that opposes me.”