Part 1 — Guardian Moon
The heavy air around Garreg Mach lingered even as its residents returned to a status quo. However, any semblance of a "normal" life did not last long.
It soon became apparent that the unusual figures in the Sealed Forest near the Monastery were, in fact, the same villains who wreaked havoc the month before and killed the Captain of the Knights of Seiros.
Archbishop Rhea intended to solve the problem without involving Byleth or his students, as she feared their hunger for revenge would make it too easy to bait a trap. But Dimitri was able to convince her otherwise through early knowledge of the situation he gathered from Marianne, as well as the argument that Byleth's Sword of the Creator could spare the church further casualties.
So she let the Blue Lions take charge, and they made their way out to the forest.
Those Who Slither in the Dark had taken residence deep within the Sealed Forest. The now abandoned stretch of the woods had been cleared out long ago, and still retained its figure eight pattern despite the more apparent paths being overgrown with vines and foliage.
In the center of the area was a large open-air arena comprised of a flat rectangle of chiseled, mossy stone that barely protruded out of the dirt with four pillars laid out like diamonds in each corner. To reach it, the Blue Lions had to circle around a clump of trees that served as the null space in the bottom half of the eight-shaped path.
Yet this was easier said than done, as the trees housed danger at every turn.
The most prominent of these dangers were more Demonic Beasts of the same ilk as those that attacked the chapel the month prior — likely also students of the Officers Academy whose fates were sealed the moment they heard the pied piper's hypnotizing call.
A squadron of masked soldiers supported each wretched monster, sporting armor with the same markings as those that attacked Garreg Mach's Holy Mausoleum and Remire Village.
Though none of those soldiers seemed particularly difficult for the Blue Lions to dispatch, the affair was made more difficult by the presence of a new threat: Kronya.
When Byleth and his students first arrived at the forested figure eight, they found the redheaded Black Eagles alumna Monica waiting. But upon finding her pray, she welcomed them to the "forest of death" with a cheery smile before literally shedding the young girl's skin.
In place of the doppelgänger shell was an unhinged, scantily clad harlequin of sorts. Kronya's true form was an orange-haired woman with ghost-white skin and a pension for spikey and black attire that read more like a natural pattern across her body than it did armor. Helping with that illusion were a number of paper-thin black tendrils that seemed to break off of her spine and protrude through the skin of her back, each tipped with a nasty orange stinger reminiscent of a scorpion's tail.
Those tendrils proved themselves to be not only threatening weapons, but also prehensile tools as Kronya bookended her first true appearance by launching two of them into the treetops and pulling herself up to disappear into the leafage.
Yet not before she offered the small armada of students a shrill laugh and the nightmarish vision of her blood red left eye, permanently etched with a black teardrop as though she had applied it with make up.
She appeared sparingly throughout the Blue Lions' march toward the central arena. Each time her presence was signaled by a bone-chilling giggle that echoed out of the tree line before one of those scorpion tendrils or her dagger-like sword Athame flew out of the darkness. There was no escape from these auxiliary attacks, which proved more effective at hitting their mark while the target was embroiled in battle against a mysterious soldier.
Kronya appeared to be in all places at once. She was able to lash out at Dedue on the leftmost approach before snagging Ashe on the arm with Athame at the other end of the forest almost immediately after.
When the panicked archer was attacked, they did not need to pull the dagger from his lithe shoulder. It disappeared in a puff of black smoke alongside the chastising laughter from the trees. That attack was what first gave Byleth the notion that one of the dark magic abilities of their opponent was, perhaps, some form of teleportation.
He carefully scanned the surrounding area as Annette, Flayn and Marianne felled a Demonic Beast with their combined magical prowess. With enough patience he started to notice the brief flashes of purple light in the darkness that signaled Kronya's appearance, and soon thereafter he found his Sword of the Creator to be a hard counter for the otherwise paradoxically diamond-hard yet slender tendrils she cast out.
Eventually she played into his hand by appearing more blatantly in the canopy branches above rather than off to the side, hoping to put an end to his retaliatory attacks.
Instead Byleth knocked her down with a quick slice of his extended, barbed-wire blade. She plummeted with a pained screech and a bright red lash across her pale form.
Though the landing was hard, Kronya quickly scrambled to her feet and began running from the relic-wielding instructor. He gave chase, leaving all of his students behind to face off against minor opponents so he could ensure the true prize — the woman who killed his father — would not get away.
Kronya clearly feared the Sword of the Creator, and kept looking over her shoulder to see how close Byleth was. With her three tendrils continually latching onto the surrounding bark and branches to rocket her forward and drop obstacles in Byleth's path, there was no chance he could catch up.
So luckily for him, her fear causes her to trip up — literally.
A gnarled root sends the assassin tumbling into the open arena at the center of the battlefield. She pulls to her feet again with an acrobatic grace to face down the Professor, who cautiously held his blade ready to strike at any moment.
Despite her overwhelming cache of magical abilities, Kronya shuttered in the face of her stoic opponent.
"But how?" She asks while shaking her head, letting her long teardrop earring jostle in the wind. "How could I possibly lose to a lowly creature like you?"
Byleth silently raises his blade, eyes narrowing as he corners his father's killer.
But before he can move in for the final blow, the Dark Bishop Solon appears behind his female accomplice.
The man Byleth once knew as Garreg Mach's librarian Tomas now had a dreadfully demented appearance where a once gentle, kindly face betrayed no ill will.
He had the same albino skin as his contemporaries, with wiry light-blue hair falling back into his dark red robe. Both of Solon's eyes were pitch black with yellow pupils, and his right eye appeared to be permanently grafted open by black staples that gave it the appearance of an inverse sun.
That large, dried out eye gazed with an unkempt energy not present in the rest of his calm demeanor, but did seem to pour out onto his forehead in the form of leading varicose veins.
Kronya's call for help was outright ignored by the decrepit mage, who demonstrated his superior strength by driving his hand straight through her chest.
"Have no fear Kronya," he says to the twitching, gasping girl as he held her up above the ground with one hand — much to Byleth's shock. "Your sacrifice will help to rid this world of the filthy vermin that have long infested it."
As Solon pulls his hand free and lets Kronya fall to the floor, his black glove with ritualistic blue patterns was covered in the same dark, slick blood that seemed to be sputtering out of her still-beating heart.
The arena is engulfed in dark purple flames that lash out and catch each of Byleth's limbs, leaving him powerless to do anything as Kronya looks up from the ground, both eyes exposed and wide with mortal fear, and begs for help.
The Dark Bishop shatters Kronya's heart, promising to unleash the "Forbidden Spell of Zahras" upon their enemies, and the woman's entire body bursts into a billowing cloud of purple energy.
That energy engulfs Byleth, and then disappears with a swirl that shifts around the dirt on the arena floor.
Once it's gone, it becomes apparent that so, too, is Byleth himself.
Solon grins.
"Be gone with you… Fell Star."
The rest of the Blue Lions emerge from the forest moments later and surround the dark mage. Many step up into the arena with their weapons raised or their magic primed, but Dimitri lingers behind.
As his lance tip drips blood near the cool stone floor, he casts his eyes to and fro.
"What was that sorcery?" The Prince asks, his voice somewhat hoarse. "What happened to our professor?!"
"They were swallowed by the mystical darkness of the forbidden spell." Solon places both hands at the top of his staff and looks toward the floor. "An eternity wandering in a void of darkness, never to return to this world… To think we almost had the Sword of the Creator…"
Murmurs of fear and disbelief mingle from all about the arena as more Blue Lions begin searching for any sign of the man just spirited away.
"That's a lie!" Annette cries, raising her glowing hands up by her face to cover some of her creeping dread. "There's no way the professor is really dead!"
"That's right!" Flayn steps up next, trying her best to put on a strong face despite how obviously she was shuddering in her loose dancer's attire. "Our professor is no ordinary human!"
"I do not believe our professor has fallen," Dedue adds with his eyes closed, as if communing with some natural spirit for confirmation.
Solon, intrigued by the outpouring, rubs his chin with his not bloodied glove.
"It is possible that death has yet to find your friend," he remarks with a slow, contemplative tone. "But there are worse things than death. Drifting through the darkness with no chance to escape… Overwhelmed with hopelessness… It must be torturous."
Though the exchange with the Dark Bishop escalates to the point of him threatening to eliminate each student, everyone's attention is drawn to the sky as it begins to glow a crimson red.
A fiery hot blade cuts into the open air from absolutely nowhere and slices its way down, opening up an iridescent rift in space.
Even Solon's pitch black eyes are illuminated by the ethereal glow of the sky rift as he gazes up at it, shock and fear replacing and bit of confidence across his features.
"So the Fell Star consumes even the darkness itself…" He mutters.
The Blue Lions are just as transfixed by the supernatural occurrence, but quickly rise to cheers as Byleth leaps into their plane of reality. He lands gingerly on his left hand and knees, the right clutching his Sword of the Creator — a sword now pulsating with red-hot light across each boney surface, much like the surface of the sun.
He stands stalwart, black outfit silhouetted by the rift he just emerged from. His once murky, swamp-green hair and eyes, which accented that serious expression, now shone neon, grassy green, flaring with energy.
The same grassy green as Sothis once exhibited.
"This should be impossible. The only being that can withstand that darkness is…" Solon scowls as he slams down his staff. "Unless I dispose of you myself, I may never have the chance to send you back there!"
With two pounds of his staff in quick succession, Solon disappears again.
The moment he does, more soldiers begin circling the bend of the top circle in the figure eight — which had a steep Cliffside as its null space to match the forest in the lower circle.
Before the approaching forces were noticed, a number of students began to surround Byleth and accost him with messages from all sides.
Some were curious as to where he'd been. Others wanted to make sure he wasn't hurt. But more still expressed deep relief at his return, the mere thought of him being dead a hard one to swallow.
As the Professor glances around to as many eyes as he could, he eventually settles on Flayn.
She was not in the circle immediately around him, but she offered a wide-eyed look of surprise at his new appearance. Mouthing 'how' and fluffing one of the drills of green hair around her head was all it took for Byleth to roll his eyes back a little and take stock of the similar shade of green they now shared.
"We'll talk about this later," he mouths silently amid the buzz of reactions.
By then the soldiers approaching from the northwest were close and ready to strike a distracted Flayn from behind. Byleth starts to push a near-sobbing Bernadetta aside with his free hand as the Sword of the Creator is raised to attack.
Yet he's beaten to her defense by Dedue, who slides in to block the leading opponent's axe strike with his heavy metal shield.
Flayn yelps and stumbles away from Dedue's guard, scurrying closer to the crowd around Byleth. As she does, Felix runs in and dispatches the attacker with a quick two jabs of his silvery gauntlets. Even though he wore his own hefty armor, the axe-wielding soldier is sent flying from the Crest of Fraldarius-bolstered punches.
"If you all are done," he says with a pant while in his follow-through stance. "We still have these curs to deal with."
The raven-haired boy straightens out his posture, and then Byleth looks around at his students with a few nods.
"He's right," the now-glowing haired Professor says. "Solon has taken to a dilapidated fort at the top of the hill. Our job is not done here."
"How do you know that, Professor?" Ashe paws at the bloodied gauze around his upper arm as he asks.
Byleth is silent as he stares up at the top of the nearby cliff for a moment.
"I just know. Trust me."
As he looks around at his students again, it's clear that they did trust him. He smiles, which almost immediately boosts the morale of each and every person.
"Ingrid, I need you to take me up there as fast as possible."
The blonde Pegasus Knight looks surprised at immediately being called out, but nods as she brushes the snowy white mane of her steed.
"You can count on us Professor!"
"Good." He approaches her with a brisk, determined stride while looking around and gesturing toward the other students. "You all hold the line here, take out soldiers as they approach. I have no idea if they'll scatter once I kill Solon, but you must be prepared for the worst."
Though that verbiage draws more nervous chatter among the Blue Lions, Dimitri steps up with his lance raised.
"Aye sir," he replies before taking stock of his classmates.
"Sylvain, Mercedes, Marianne." Each of them looks up at his beck and call. "Join me on the eastern front, if you would."
Dedue steps up and pounds the side of his axe against the armor on his chest, letting its clang resonate.
"You can count on me not to leave your side, Your Highness."
Dimitri smiles to his vassal before turning his attention out to the rest of the class again.
"Felix, you and Annette lead everyone else as front-and-back forces to the west."
As if to give assurance of their capabilities, Annette was already turned to the outer edge of the arena where she blows an approaching halberdier away with a harsh blast of air-slicing wind.
She looks back at him over her shoulder and flashes a grin.
"Understood! We won't let you down, Your Highness."
Felix acknowledges him with naught but a grunt, yet the sentiment comes across.
While they all take battle positions, Byleth jumps up on the back of Ingrid's saddle and she immediately takes off. They quickly lose all track of the activity below as they escape gravity, wind roaring in their ears.
The Pegasus soon offers Ingrid and Byleth a bird's eye view of the entire battlefield, where the soldiers may as well be ants. He points out the collapsed fortification at the top of the hill and directs Ingrid to descent upon it, but ensures they approach slowly and with arcing loops to avoid any incoming projectiles from the magically inclined villains below.
"I'm glad you're okay Professor," Ingrid manages over the wind to the man behind her.
He responds with a smile and a reassuring squeeze around her waist.
She smiles back.
"I also quite like the new hair color, wherever it came from."
Their idle chatter does not last long, as a screeching Banshee spell narrowly misses the Pegasus' wing and they take evasive maneuvers, dive-bombing the fortification before Solon could charge another attack.
Ingrid swoops by the spot and drops Byleth off before going back down the steep cliff to join her classmates.
Byleth turns to his foe, determination burning in his eyes nearly as bright as the glow of his sword as it's raised high.
"Your snare was a cute trick," he says.
With a sharp swipe of his sword it disconnects into that extended whip form, the blazing pieces surrounding his body in a wide ring like the electrons around an atom.
Solon closes his eyes (though the right one remains open all the same).
"I am terrified by you… Even though an emotion like fear has no place inside me." The Dark Bishop raises his staff high with both hands. "That means you must be eliminated."
Soon the staff is awash with cloudy purple energy as he clutches it tight. Byleth retracts his sword in turn, and then rears it back like a bat.
With a harsh and gravelly call, Solon slams his staff down again and looses a fast-moving bomb of poisonous energy toward the Blue Lions' Professor. Byleth cuts the Sword of the Creator in front of his body with a long, horizontal swipe; the weapon once again splitting into a barbed whip in the process.
The Heroes' Relic passes through Solon's Miasma spell like a hot knife through butter and utterly obliterates it. But the Godly power pushes even further, slicing Solon's staff in twine and sending him flying from a sharp thwack to the stomach.
The Dark Bishop cries out in pain as he lands hard on his back, clawing at his practically eviscerated stomach through the shredded robe.
Byleth's face is as stoic as ever when he steps up onto the ruins of the fort where Solon once stood and casts his gaze down onto the fallen foe.
Solon gasps for breath as he glares back up.
"To think… That I would lose to mere beasts." He starts to fall limp, voice shallower with each passing moment. "But this is not the end… Thales will carry out our mission, somehow…"
With those final words, the self-titled "Savior of all" dies like a dog, bleeding out in the dirt.
Byleth simply looks on from above, embracing his newfound divinity.