April 1st, 71 BNM
Dawn
Mid-Western Equestria, Mountain Range
Tartarus prison fortress

Not every scout had been captured, and while the full extent of the enemy was yet to be determined, the warning bell had sounded.
A large gong reverberated from atop Tartarus’s mountain ridge, and the pyre had been lit to signal for aid, the distant pyro on a mountain top 5 miles away already alight as well. Messages had been sent, any help was welcomed.
But the sounds of an advancing army echoed in the valley as the gong of Tartarus fell silent, the calls for help sent out.
Rushing out to the rampart, General Slickhooves stopped as he came to shuffle through a line of archer ponies that had taken up position, a mere fraction of 3000 other garrisoned ponies of all kinds that stood fast to defend the immense fortress.
“How many?”
“10,000 at least, 15 at most.”
The archer captain’s reply did little to ease Slickhooves’s nerves, but the black Pegasus merely leant over the rampart to see the other towers and walls along the mountain ridge being filled with stationed guards, catapults and ballistae made ready.
Vats of oil were heated by Unicorn magic, made ready in case the bridge was taken or the chasm between the mountain walls and the slopes bridges somehow by ground forces.
Staring out, the General saw the specks that were the Nationalist armies amassing, pouring around the valley rim to the east like a horde of ants attacking a picnic. Flying ones above them confirmed pegasi were among the hordes.
Beside him, a Unicorn corporal pointed out to her superior:
“They’ve got siege weapons, looks like they know they might be in for a long battle.”
“They’ll send in air attacks first, probe us. Archers, be ready! Protect the siege turrets, we’ll need them when the horde comes upon us!”
As Slickhooves bellowed out, a loud echo of archers coming towards the front of the ramparts across all the walls rose into the dawn air.
Ahead, the army pressed onwards.

Tartarus valley

Murky white and blue colours flowed everywhere, the Nationalist armies marching down the valley in their horde, war drums and chants resonating over the thousands marching to battle before them.
At the forefront, a few of the soldiers gulped at the sight of Tartarus’s foreboding walls, imbedded into the mountain ridge two miles ahead. Many of them were conscripts or fresh recruits, fresh blood for battle in the worst cases, and fought because their landowner nobility wished it of them.
The Nationalist legions marched forwards, with the Pegasi surging ahead.
Near the front of the advancing army, the white and teal maned Unicorn mare gave orders to the generals:
“-siege engines ready, and have the magic divisions sent up once the wall has been reached.”
As the armies advanced, Teal turned to Aubelles, who was pacing beside her now in his bronze armour:
“Aubelles, there are two other Alicorns in this army with us, you know them I presume?”
“Yes, we have spoken…”
“And you know what I have ordered you and they to do?”
“Yes. But if I may, even for 3 Alicorns, going head on against that fortress is not daring, but foolish.”
“So much for your bravado then…” Teal remarked, to which Aubelles sternly spoke to her as he turned his head to face her, still marching beside the Unicorn mare he had to tolerate as his superior:
“You show contempt for sending me and them into their waiting teeth, yet you are one to sit back and wait with the armies. You may not know it Teal, but you have given me, and those two, an opportunity to prove why experience will trump assigned authority.”
“I don’t understand your outrage. You and those other two are Alicorns, you should be fine, unless you aren’t as powerful as some tales tell. Besides, I expect you and they to be an inspiration and a boon to this battle, regardless of your fates. Now go, and fight as you would best when you get there.”
Aubelles stared at Teal Quirt, the Unicorn that so callously had stated she cared not for what happened to him and the other two, her contempt for Alicorns clear.
“We’ll have words about this when I return, believe me!”
As Aubelles spread his wings and took flight, a few of the soldier ponies in the hordes cheered him on, as a pair of other Alicorn soldierss that had flown up further back flocked to join him. Still marching with the army, watching the Pegasus squads already having reached the fortress from afar, Teal Quirt couldn’t help but smile lightly at the prospect.
If any of the Alicorns fell in battle, it was merely one less in the long run.

Tartarus prison fortress

Arrows flew, flaming and magic enchanted, across the skies, the hundreds of Nationalist aligned pegasi darting and firing their own weapons, be they back-mounted crossbows, fire and tar bombs and some special weapons.
A rampart tower went up in flames as a cluster of fire bombs were flung by a daring Pegasi squad, archer ponies screaming while others fired back, a few pegasi spiralling down from hits to down them, arrow or magic.
A Unicorn stallion captain hollered to keep firing, his own magic shooting a diving pegasi mare out of the sky with ease. But as she fell, her other companions, 2 stallions, released their weapons, which began to miraculously glow as they shot towards them.
A sticky ball the size of a crocket ball stuck to his flank, glowing and feeling very warm as it gently hummed against his flank. Wrenching to use his magic to rip it off, the Stallion felt it seize to his fur, before he gave it another tug.
The rampart wall he stood on was engulfed in a bright white explosion, the bomblet disintegrating the stallion in a superheated grey puff of smoke and dust, a few fragments of fur and armor flying from the blast.
“Watch yourselves! Curse balls!”
Curse Balls, an invention that originated from the mages of the Royalists, but very quickly defected to the Nationalists under bribery. Magic spells turned to potions of simple, one time use, with a wide range of surprises when they went off. All of them stuck to whatever surface they landed on, though more and more had been shown to actively seek enemies like bees.
Both sides used them, though they were usually weapons of infiltration or for smaller conflicts, not large scale attacks.
Disintegration into dust and ash, torture, stun shots, or even magical tracers. Designed to give soldiers of non-magic a one-time use means of basic magic to be made combat available.
Tartarus had its own stockpile, and made ready to use theirs in turn.
But ahead, as the rain of arrows and fired spells continued to fly, a trio of heavier magic attacks rained down from an incoming flight.
A new wave of a hundred pegasi approached the walls, led by 3 more armored ponies in flight. One of them sporting bronze armor.
The magic of the Alicorns cut across the rampart walls like a scorching beam, but the walls were merely burnt, not broken. Enchantments lay on them that flickered a faint glasslike fog, strengthening the walls beyond what their stone makeup would give them.
Diving headfirst into a maelstrom of arrows, Aubelles’s shield took a battering as the pegasi group split up, aiming for the flocks of archers along the lower walls.
Swooping low, Aubelles’s magic swept along the wall like a broom, sending Earth ponies and Unicorns flying as he smashed through them, flying upwards.
He winced as a number of arrows and spells flew his way, the sheer volume of them at this range enough to overwhelm him.
An Alicorn could defend against incredible attacks, but not from so many different directions and sources, without it becoming too much.
Glancing around, as he flew further up, Aubelles saw the youngest of the other Alicorn soldiers take a spell shot to her flank, forcing her to dive away to recover for a moment, while the other Alicorn stallion visibly was straining to keep his shield up as a heavy barrage of spells and arrows filled the skies as he made another pass.
Down on the ramparts, Aubelles didn’t need to hear what was bellowed to know what he and the others had inadvertently become:
“Focus on the Alicorns!”
While the hundreds of Pegasi flocking and diving before the quarter mile long rampart walls were fired on heavily, the 3 Alicorns became a prime target whenever sighted.
Grunting at the prospect, Aubelles cracked his neck, bellowing aloud for the pegasi and other 2 Alicorns to hear:
“Show them real hell!”
Diving down, Aubelles rejoined the fray, muttering as he drew in closer to arrow and spell range once more:
“I’ll live to tell this tale, I swear it!”

Opposite mountain ridge

Gazing at the unfolding battle, Chack could use the magic of the sword of Everfree to see further than normal. The Pegasi hundreds and 3 Alicorns were darting across the walls, taking out archers, Unicorns and the occasional siege turret.
But the fort was immense, and the fliers were in a storm of defence that could afford to fire from cover.
And Chack could see his friend was right in the midst of it, something he never did.
“Why Aubelles, its suicide… But maybe that is it.”
Glancing at the advancing army in the valley, getting into position to set up defensive lines in the valley already, massive siege engines forming into place 500 yards from the castle, out of the range of the arrows and spells from the actual fortress itself. Normally they might place the siege weapons, ballistas, catapults or the newer Trebuchets closer, but given the sheer size of the fortress, accuracy was not as crucial. And with some of the clearly magic laced weapons, as it seemed surprises from more than just Alicorn soldiers and the Citadel were in play on both sides, accuracy was even less of an issue.
But staring across at the unfolding aerial conflict, which as the forces were continually peppered, the sheer defence of the heavier siege turrets tough for even the Alicorns, Chack found himself growing worried.
Without pause, knowing he would have to take part in the battle at some point, he darted off down the mountain slopes, Everfree blade and his trusty katana in hand.
He sensed only the being of Envy here amidst the armies, but it was too hidden. For now, he’d wait, until the battle was more progressed, before he made his move.
In the meanwhile, he had concerns for a brother in arms he’d not seen in a very long time before now.
His magic sword making him invisible, Chack clambered down the steep hill face towards the plains a half mile below, knowing the battle was far from even begun at this point. He would have to get to the base of the fortress, or into its walls, the hard way.
He just hoped that the Royalist reinforcements were ready for what was on track to arrive by nightfall tonight from the north east.
By the time he’d reached the valley’s river in a half hour, the first of the Nationalist ballistas had fired, a shot to probe the range on the many siege weapons being set up in its ranks. And in that time, the siege turrets in the fortress had only lost two.
The enchantments and stone of Tartarus was too much for all but the most dogged of aerial assaults, as dozens of dead pegasi already showed, Chack glimpsing their bodies falling like flies onto the slopes, or even vanishing down the moat like chasm between the slopes and the mountain wall.
The first of many to come in the battle.

Late Morning
Nokotaford, Royal Palace
Main atrium

The palace was in uproar, the pyre beacons, magic message letters, all calling for reinforcements to Tartarus, clearly the 3000 stationed there insufficient against the perceived enemy already assault the fortress.
Her advisors and two generals beside her, her black dress matching her dour mood, Queen Aurora nearly barked to them as she advanced to the main foyer:
“I want them there by nightfall, any that can be spared! Every soldier, every reserve, don’t let them seize Tartarus while I still draw breath, or heads will roll!”
“Yes your majesty!”
As a few of her advisors scampered away to their duties, the older General Pegasus leaving ahead of her, Queen Aurora magically stopped the younger General, a Unicorn Mare, as she spoke lowly:
“General Fleecehorn, send word to General Slickhooves, though I expect he may ask if things go badly. You will gather those trained enough, tell him the secret weapon will be ready to use by their arrival there. It is time the Nationalists learn the full extent of what we have unlocked, they are not the only side with powerful forces to unleash.”
With a quick bow, General Fleecehorn darted off to send word to the few elite Unicorns and non-nobility Alicorns by any means to head to Tartarus. Turning away, Queen Aurora stared out the window in pondering thought, murmuring lowly:
“Retribution for Canterlot at last…”
“Mother, we’ve heard, what is to be-!”
“Be still daughters, reinforcements are on the way to Tartarus, and the enemies shall be repelled with as much mercy and swiftness as they attacked with when everything is in place.”
Queen Aurora spoke as she turned to see Celestia and Luna, the pair of them having darted to find out what was going on. As a moment of quiet came upon them, Celestia asked bluntly:
“You authorised that secret weapon to be used, didn’t you?”
Aurora nodded without pause, as Luna looked at Celestia with some uncertainty, before she saw the look in Celestia’s purple eye before she spoke after a brief sigh:
“We can’t sink to their level mother…”
“They deserve as much.” Aurora remarked bitterly, to which Luna quietly replied:
“Must it be used full force? If we could use it to ward them off-.”
“They attacked, retaliation is justified at this point. It has been for too long.” Aurora replied, to which Celestia’s next request came as a surprise:
“Then let me go. I’ll see it is done in the best way for all.”
As a few servants rushed by, respectfully averting their eyes from the exchange in their hurrying to their duties, Queen Aurora turned to see Celestia’s staunch tone and stance before her.
“No.”
“I won’t be in battle, and that advanced magic is much more controllable in Alicorn control.”
“..And when were you going to inform me that you’d used your royal status to probe secret research behind all of our backs?” Aurora asked sternly.
Luna’s eyes turned away, a light cough under her breath as she replied:
“Umm, not all of them.”
Turning to Luna, Aurora at this point wasn’t surprised: “Of course not, you two hardly ever keep secrets between each other… But my word is final!”
“We have a duty to serve our people, and if we can minimize death all around-.” Celestia began, but not before Aurora sternly walked towards the elder sister, the Queen replying darkly:
“I will not let my two daughters walk into a warzone...”
Luna then spoke up calmly, a level head between the mother and her elder sister:
“Let us help with the weapon, and it won’t be one for very long, with less death as a whole.”
Looking at her two daughters, Aurora blinked a few times, asking incredulously at them with a voice mixed between gruff disdain and hysterics:
“And what would you do? Use it in warning only? Ward them off, they aren’t so easily frightened!”
“Is it not worth trying to avoid such cost, just for once? They are ponies, like the rest of us, enough to see sense. Let us go mother, don’t let protecting us cost needless lives…”
As Celestia’s words rang true, Aurora then heard Luna speak up, the smaller blue Alicorn gently walking up behind their mother as she spoke in her serene voice, more certain now then ever before:
“If Equestria is to ever be united, we must give the other side the chance to see sense…”
Turning to face the atrium’s window, Aurora saw the faint reflection of her two grown daughters in the glass, and her own downcast eyes. Shutting them, she spoke calmly:
“The moment you are in danger, return. No less.”
Looking at each other, Celestia and Luna shared a smile, the elder sister proclaiming confidently to their mother as they turned to leave:
“We will make you proud mother.”
As Celestia wandered off, Aurora turned her head to see her white elder and blue younger Alicorn daughters galloping down the halls, catching up with the wandering General Fleecehorn about the secret weapon of Tartarus.
“I always have been, as was Nova.”
Turning back to the window, Queen Aurora delved deep into her thoughts for a moment, before more becks and calls from panicking advisors about the mobilisation of Royalist reinforcements came back around yet again.

Meanwhile
Royal palace, front gardens

Glancing around, she couldn’t help but feel sorry as she saw the drowsiness and rather laid back state her passing left in some of the guards on duty. It was amazing how ‘mellow’ the once alert guards appeared as she passed by, even invisible.
Lady Ave-Dol sensed about, darting into a palace garden so as to avoid ‘slothing’ any more guards. Unless she was in her ‘unnatural’ form, she always gave off her field of relaxation and lethargy inducing magic, also causing drowsiness and mental slowing to convince them to be truthful, or even temporarily forget things.
But she searched for a magical presence unique from others. Using a spell, she probed the castle, her hoof pressing into the grasses as she hid amidst some pony shaped bushes.
The castle and grounds were roughly shown before her eyes in her mind, she sensed many presences, a lot of weaker to medium powers, and a handful of very powerful signals from Alicorns, royalty or those there for other reasons. Oddly, four of them were altogether whilst the strongest, likely the queen, was alone.
But it was in a more closed off area, where a diminished magic signal, older than others, resided that interested her.
Sensing the bearded wizard was in a smaller, lower level chamber, the invisible Alicorn made her way through the castle gardens, already knowing some staff passages she could use to avoid the main atriums and hallways.

20 minutes later
Late Morning/Midday
Royal Palace, Infirmary chambers

Passing through, invisible to the naked eye, Ave-Dol sensed a mere handful of ponies in these chambers, asleep and resting, making the magic she gave off redundant here. But the single chamber nurse on duty might be affected, which meant a necessary enchantment was needed.
As the Unicorn mare rounded through the doorway leading from Starswirl’s chambers, she turned to see something shimmering and blue materialise in the chamber before her, amidst her lesser patients’ beds.
It resembled an Alicorn mare, but it had a flaming feathery mane, and a shimmering glasslike body of a Windigo of all things. Staring at her with piercing blue eyes, the creature slowly advanced, a wispy voice carrying from her:
“Please, do not scream, I mean no harm…”
“No…Harm…” The Nurse’s eyes dilated, as a blue glint overtook them. In her vision, this strange creature suddenly morphed into a blue bodied Unicorn nurse who had come to relieve her. To anyone else, the creature appeared as it had at first, the deceit on one pony only.
“Yes. Now, open the door, and lock it, I must tend to him alone.”
“Very well… Do not be too long.”
As the nurse pony obliged blankly, opening the door to the darkened infirmary room, Ave-Dol nodded in appreciation to the nurse, passing by without a word. As soon as she was through the doorway, the wooden door creaked behind her until it shut.
Turning to leave, the nurse pony’s eyes slowly returned to normal, as she put a hoof to her head with a small groan:
“Wha-Was I always this, maybe I should take my break early…”

The Alicorn/Windigo/Phoenix hybrid stared at the bedded Unicorn stallion, his rear leg clearly swollen and infected, by more than just mud and bleeding from his ordeal over a week ago in his stint in the Citadel.
Sensing with her magic, Ave-Dol sensed dark magic at work, the tell-tale signs of disruptive magic of a green hue that Teal Quirt perfected as a form of long term attack to anypony who she couldn’t deal with immediately. A magical disease of sorts, embedded into Teal’s mutated body’s scorpion claws.
Her own magic, the ‘laxing’ field actually helpful here, began to slowly peel away at the mental barriers and blocks caused by the green magic infecting Starswirl, as well as his own magical barriers in his subconscious.
“It is time to see both sides…”
She probed deeper, hoping to pierce the Wizard’s mind and shed answers for herself, and give him insider knowledge from another who could see Siral for what he had become now.
She merely hoped it wasn’t too late for this exchange.

Later that day
April 1st, 71 BNM
Mid Afternoon
Mid-Western Equestria, Mountain Range
Tartarus prison fortress

The stones and projectiles were hurled back and forth at distances over 500 yards, be they normal boulder, one use potion/magic ‘warheads’, as the trebuchets, catapults and ballistas mounted on the wall and brought by the army exchanged blows with no remorse.
Stones crashed into the ground of the army, a few soldiers taken out, but there were the magic forces as well, many of them deflecting the non-magic shots altogether a lot of the time.
A warhead projectile launched from Tartarus’s wall smashed into the ground, but on impact a sizzling disc of red magic shot outwards, slicing a few unfortunate soldiers in half and blasting back those further away like being struck with a whip. Disintegrator warheads rained down, some homing in on targets and detonating on impact if not shot down before landing.
Nationalist Earth ponies advanced, holding thick shields aloft in formations to keep dozens at once protected across the plains as they slowly began to march up the hill towards the fortified mountain face.
The walls and ramparts of Tartarus flickered with the watery/glass like magic rippling, the centuries old collection of enchantments reinforcing the walls holding firm, even if not protecting the soldiers on the outermost reaches as much.
Nationalist pegasi pulled back, as the attackers had focused their archers and magic users around the siege engines, making the targets too hard to hit now.
Amidst the hundred dead pegasi from the expected high casualties, there was also the one slain Alicorn stallion, peppered with half a dozen magically enhanced arrows and even more spells as he fell wounded from the skies.
A faint green mist floated off his body as it finally stopped rolling down the hill, that magic that evaporated off all Alicorns in death emanating off him giving a morale boost to the Tartarus defenders.
Hauling the other, wounded Alicorn mare from the aerial battle, Aubelles flew over the multiple divisions beginning to march up the long hill climb to Tartarus itself, as the bombardments went back and forth between both sides, casualties in the hundreds already for the Nationalists, and less so for the defenders.
Bitterly, the Bronze Alicorn would relish when the walls came down, and the cowards could stop hiding. The enchantments and stone wouldn’t last forever as more and more siege engines were set up, and the army advanced on the base of the walls itself.

On high though, climbing up the long walls of Tartarus, having leapt across the chasm enough to begin literally stabbing his magic enhanced sword and katana into the wall stone to climb, a single Salamander made his way up.
Chack knew the real battle would be upon or within Tartarus itself, and he ignored the exchange of arrows and spells high above, and prayed that a stray boulder or magic warhead didn’t find hit him as his invisibility field kept his climb unseen.
One such stray boulder smashed the wall a dozen metres above and left of him, prompting him to freeze as debris from the shattered warhead rained down to his left, a translucent ripple of the magic coming from the walls themselves.
The fortifications wouldn’t last forever, that was certain. The battle would retreat inside, especially given the heavier hitters on route to aid the army’s assault.
And inside or at the gates would be where he expected at least one of the seven he needed to target to be. He only needed one.

Author's Notes:

Part of a multi part ‘chapter’ in this story, as a lot of things come to head. But this battle is far from the end of the story as a whole, but the ‘beginning’ of a major turning point.