Dusk Shine's Fatal Flaw

"Princess."

The masculine voice was slow. It wasn't loud, yet it radiated throughout the main hall of the Castle of Friendship.

It was a voice she immediately recognized, but its timbre was all wrong. There was a deep and powerful quality to it that she also recognized, but from somepony else entirely. Bits and pieces from two different individuals she had once held dear rang in Celestia's ears. Her gaze drilled two holes into the one at the top of the staircase.

With a gradual step, the pony left the shadows.

And her heart dropped.

She thought that a month of preparation would have been enough for her to come to terms with what she needed to do, but time after time today, she's found herself dreading it more and more.

How could she not when staring at the tainted form of her precious student?

'Dusk Shine' had his head held low. His mane was longer than Dusk's, so much in fact that it hung over his eyes and dragged on the ground along with his tail. Across his body, Dusk's colors were present but darkened and near black in some places. His horn was straight and came to a sharp point. His wings were proportionally larger than Dusk's ever were, even compared to her own.

The stallion was wearing a recognizable set of regalia. Sombra's silver armor was resized to cover the larger male's neck, chest, and lower legs. A deep purple cape styled like the previous King's was worn over his back, modified with new holes for his wings. On top of his head, partially obscured by his mane, was Sombra's crown holding Dusk Shine's Element of Magic.

There was so much wrong with what she was seeing. Celestia stood at the ready as the stallion before her descended the steps. Her head lowered as his slow gait brought him to her level. When he finally stood before her, Celestia realized that she was still looking up, that this stallion was taller than her.

She didn't say or do anything at first, neither did he. The mare couldn't see the stallion's eyes under his mane, but she could feel his gaze.

He made the first move. Celestia readied her horn and took a defensive stance. She expected an attack of some kind. Whether it have been a physical strike or spell, but neither came. Instead, The-One-Who-Called-Himself-Dusk-Shine buckled his forelegs and lowered the front of his body to the ground.

He was bowing to her.

"Prin... cess." The word was drawn out like it took great effort to say. He lifted his head to look at her, his mane shifting to allow Celestia to finally see his eyes.

He had Dusk Shine's eyes.

The entire display was a lot even for her.

Despite all her years of rule, despite all the lives she's outlived, despite all the decisions and all the personal sacrifices she's made, Celestia could never part with the piece of herself that cared far too much. It was the piece that held a firm attachment to a select few, a piece that she'd try to suppress during times of great need, but could never do so for long.

So, when the stallion righted himself and charged at her, Celestia hesitated. She had the time and power to ready any spell or prepare any defense, yet she chose not to. His body collided with her's and she did nothing to stop it.

"It's so good to see you, Princess." He hugged her tightly. She could feel him shaking. Despite his size, he felt so brittle for a moment. "It has beena rough month."

He pulled away. His mane had shifted, again, which revealed his smiling face to her. It was Dusk's smile. The same smile he made when he showed her a newly mastered spell, when Spike took his first steps, when he finally got to see a friend after a long time apart.

But he wasn't Dusk Shine. This stallion was just wearing his face.

"Back... up."

"Princess?"

"Back away from me this instant!"

The stallion braved the Royal Canterlot Voice without moving. He looked shocked before his expression melted into resignation. He stepped back two lengths.

"Princess Celestia." He was muttering desperately. "I promise I have an explanation for all of this. There's this spe-"

"I know what Fusion Magic is, Sombra."

There was a long silence between them. The stallion stood for a moment before falling to his haunches. He was stunned at first. She could see the gears turning behind those stolen eyes.

"O- of course. If anypony were to know, it would be you." He focused his gaze back on her, that stolen smile timidly on his face. "But then you know what I am. You know I'm not a threat. I have my Element here to prov-"

"'Not a threat?'" Celestia spoke lowly. It didn't take much effort to put some anger behind her words. "After all you've done, after enslaving your own subjects, after attacking the Crystal Empire on multiple occasions, after stealing my pupil's body to enhance your power, you expect me to believe that you are not a threat!?"

Like before, the Royal Canterlot Voice didn't seem to affect the stallion like it would a normal pony. However, he shifted uneasily under her glare and hung on her words, thinking about what to say next.

"I- I don't...."

"You don't what, Sombra?"

"Dusk Shine.... Please." His voice got quieter as he spoke. "I'd prefer to be called Dusk Sh-"

He felt the attack coming before actually seeing it. He threw himself to the ground before Celestia's hoof could connect. The alicorn princess then stood over the laying stallion, her Sun's shine came through the windows behind her to silhouette the princess in its light. The only detail he could make out was the dangerous glow of her eyes.

"Silence, Sombra! I once put my trust in you. You were my deepest friend, my confidant, my fellow ruler, but you threw that all away. There was a piece of me that was foolishly hopeful upon the return of the Crystal Empire. There was a chance you'd be there, a chance that with new found power we could restrain you and talkyou out of your decisions.

"It was so stupid; I was so stupid. I just wanted you back. I was the luckiest mare ever to have been blessed with my sister's return. Now, I'm the most foolish for expecting the world to give my love back as well.

"I put so many others on the line for you and for what? I've lost my student. You took him from me with a spell my mother spent her life eradicating. He will never reincarnate. He's gone with you."

"The Prince of Friendship was the one to introduce the spell."

It was so quick and simple. Dusk Shine was good at that; being able to find just the words to say if you gave him the time to think. It's what made him such a breath of fresh air when otherwise confronted with nobles who always found the need to inflate everything that came out of their mouths.

Celestia reeled away from the stallion.

"My namesake was the one to approach Sombra with the spell." He stayed on the ground, eyes directly meeting hers. "He was the one who explained fusion and even pushed for it when Sombra denied him."

The Princess couldn't begin to fathom it. So many questions were popping into her mind to an overwhelming degree. However, they would have to wait.

Wordlessly, Celestia dug the sharp end of her shoe into the crystal flooring. She ignored his questioning look as she carved a symbol. With a flourish, it was done and she moved onto the next. It wasn't the most dignified or safe way to create such a rune, but she has had a lot of experience over the years using any number of implement.

The stallion continued to lay there as he watched. "A glyph?" He frowned. "Teleportation?"

"Did you pry that information from Dusk Shine's studies or Sombra's experience?"

He grimaced. Was she being too harsh? He certainly wasn't acting like a threat. Yet, acts were meant to be deceiving.

They both wallowed in silence for a few moments. Celestia continued her work even as the stallion perked up. His head turned to focus on a rapidly approaching signature.

"Cadance." He looked excited, eager even.

"No." Celestia held out her wing, stopping the stallion from moving. "I won't let you see anypony until I'm certain you're safe. I hope that isn't an issue." The amount of venom in her voice squashed any objection.

"Yes, Princess." He looked so dejected. She decided to pay him no mind and just focus on the task at hoof. "May I leave them a note?"

Celestia didn't respond and just continued her work. She had just about finished a full circle when a quill and parchment appeared before him. He nodded in thanks, that weary smile on his face, as he began to write. Oddly enough, he held the quill in his hoof as he wrote instead of using telekinesis. A habit she didn't recognize from either of his donors.

They both finished their tasks at the same time. He fashioned the letter into a little airplane and let it fly out of the room towards the kitchen. How unusually childish. She let her magic flow into the first sigil, which caused them all to light up.

"Prepare yourself." Celestia stood within the circle.

The stallion got up and stood by her side, his gaze drifted toward a wall. Through it, she could feel her fellow princess' magical signature closing in. She must've been galloping down the halls now.

'I'm sorry, dear niece. I'll make this up to you.'

"I'll make it up to you all."

She cast her eyes to those of the stallion. Those stolen eyes shone with a familiar determination. One that reminded her of two very distinct, yet ever similar ponies that are dear to her.

'Were.' She reminded herself.

. . . . .

There was a reason Rune Magic was so rarely used as the years waned on. It cost the user less magical energy to cast, yet it took time to set up the necessary runes to form a complete glyph; each of which had to be recreated to perfection or else the desired effect would never be reached.

That was in addition to the advancement of technology. Why bother having a series of unicorns power a movement rune for a train when a steam engine would allow anypony to perform the job?

However, as all things, it had its uses.

With a bright flash, Celestia and her companion warped into existence. The stallion looked around inquisitively.

They were in a cave-like room, its walls and floors carved from rough stone. It was mostly barren, barring a kitchenette and sitting area pushed off to one corner. There was also a severe lack of any doors or windows.

"Where are w-" The stallion cut himself off, his head swiveling around.

Celestia didn't blame him. Once one became used to sensing the magical signatures of every living thing around them, their absence rang like a deafening silence.

"This is an old safe house of mine. Sparsely used over the years and left abandoned until I refurbished it before Discord's reformation." The princess gestured to a table with a wing as she walked around it to the kitchenette. "Located deep within Mount Canterlot, it was constructed with materials from the mines that would spark the founding of the Crystal Empire. No magic passes, impacts or escapes these walls."

"Anypony who enters would be trapped unless they knew the exact location and combination for the exit portal." The stallion spoke with a bit of awe in his voice as he studied the runes at his hooves. It sent a pang of familiarity through the mare. She could see either of the stallion's donors giving the same response. "Wait, we're under the Pillar of Twilight?!"

Celestia raised a brow. Dark purple wings were bristling and lavender eyes contained pinprick pupils. Where had this fear come from? Had he just realized the situation she put him in, or was there something else spurring that feeling?

"That's the mountain's original name, yes. Although, I'll remind you that it hasn't been called that since I declared Canterlot as the capital of Equestria."

"Yes, of course." He muttered quickly. "To confirm, this room isn't connected to any tunnels or passageways, correct?"

"No, I made sure of it myself."

The stallion oddly sighed in relief. Celestia narrowed her eyes for a moment. Shouldn't her confirmation ring as a bad thing to him? Shaking her head, she once again gestured to the table. "Take a seat, please. We can discuss things over tea."

The room was mostly silent as she prepared a pot. When she turned to face him, she saw that he had yet to move from his position. He was looking at her quite oddly.

"Don't you hate tea?" He said. "Or is that something that changed with time?"

Celestia didn't respond.

"Sombra clearly remembers you admitting to hating the stuff. That would make me lean towards the latter, but then, again, the Prince of Friendship doesn't actually remember you ever drinking any. Every cup you were given always seemed to be mysteriously empty." He chuckled as he made his way to the table and took a spot. "Not that it really matters, but I'll be the first to tell you 'I told you so.'"

Celestia held her breath for a moment before letting out a long sigh. She used her magic to place down the pot and cup near the stallion before sitting across from him.

"I know, I know. But they looked so earnest at the time. I couldn't just squash their little heart. Then one batch turned into two, which became a weekly shipment to the castle."

"Of course, Tea Leaf would earnestly wish to share her craft with the Princess of the Sun, and of course, that craft would be tea. When I was offered that hideous portrait, I smiled, thanked the artist, and moved on. I di-" The stallion stopped as realization struck. He took a moment to catch the mare's eyes, a mirthful little smile gracing his lips. "You got the stainedwindows?!"

Celestia groaned and covered her eyes. "Please don't start. I get enough of that from Luna."

He chuckled. "Riiight. Luuuna. Your siiiister. How did that come to be? Your parents aren't still out there, are they?"

"She's my best friend and I'd think of her no other way. Regardless of blood."

"And Cadance?"

"I'm sure if you put your minds together, you'll figure it out."

"Prince Blueblood?"

"Distant relative of Clover the Clever. His entire family line has called me 'Aunty' for about two millennia now. The fact that his family name is 'Prince' is completely unrelated."

"Dusk Shine?"

"He was a dear friend and a most faithful stu...."

Was.

The atmosphere between them chilled.

"I'm right here, Princess."

"You may be, but my student is gon-"

"No, I am not, Celestia!" The stallion slammed a hoof onto the table, cracking the reinforced material. "I have all of his hopes and dreams and memories. I feel as he did, as I do. I know I'm not the same as I was, but I am Dusk Shine. I just have more to me than before."

"'More to you?" The mare straightened herself. It was as if she was lecturing a rather daring, but foolish noble in her court. "If I mix blue and yellow paint, can I truly look at the green and still call it 'blue?'"

"If the paint was sentient and capable of claiming an identity, I'm sure it could convince those closest to it!"

"Dusk Shine would never lash out in his anger." She gestured to the now damaged table. "He's never addressed me without my title."

"Sombra didn't either at first. As I became familiar with you, he dropped the semantics, I'd do the same as Dusk grew more comfortable. That's how friends behave. They bond, share and don't sit around while another is disrespected."

"Calm yourself, alicorn." Celestia's voice darkened. He stuttered at her tone. "Before, I could recognize who I was speaking with, but now your identity is slipping. Dusk Shine entered this place, Sombra teased with me about those windows, and now the husk of what they once were has damaged my table."

"H-h- I am me." The stallion gibbered to himself. His head dropped, causing his mane to cover his eyes. "I. I. I."

Celestia just watched the display in front of her with a small shake of her head. She's seen such a reaction before. When two ponies of equal experience were merged, their identities tended to conflict. In the past, the fusion would simply choose a new identity, one which saw their progenitors as parents. There would be no reason to try and disregard one of their histories to adapt to just one. That would just hint at a deception of some kind, but then again, who was to be deceived?

Shame of one's past was a powerful motivator.

"Princess?"

When he got her attention, she felt the need to do a double take. The stammering stallion, near a mental break of sorts, had calmed and was looking at her with focus. That was certainly fast.

"I've kept you waiting." He bowed his head in apology. "May, I ask why you've brought me here?"

Had she been waiting? Celestia's connection to the Sun may have been broken while in this room, but her internal clock stated that barely a minute has passed since she last spoke. Another concern for later.

"This safe room isn't to keep any one pony safe. It's to keep the masses safe from one pony. If our conflict couldn't be contained to the Castle of Friendship, this site would be known as 'Celestia's Last Stand.'"

His eyes widened. "You think I'd attack you? That I'd strike you down?"

"You've done so before. Have you not, Sombra?"

"Dusk. Shine."

The two just stared at each other, the tension building.

Celestia allowed her stoney expression to fracture a bit and adopt a small smile. "No, I no longer think you'd attack me so brazenly. From what I've seen and felt, you are not a threat." She saw a bit of hope in his eyes. "However, that does not mean you have my full trust, nor that I don't have questions."

The stallion took a calming breath. "That's understandable. Please, ask away, Princess."

"I have something else in mind." She focused power into her horn, which spread until coated it coated her body in its aura. A single strand roped off and to float loosely in the air between them.

He stood and urgently backed up. "That is-!?"

"Do not be alarmed." Celestia cut off gently. "This is not the spell you are thinking of, I'm simply borrowing aspects of it. Are you familiar with my sister's Dream Magic?" She got a nod. "I'll never be able to accomplish the incredible feats my sister has, but I've learned what I could. Combining that knowledge with Fusion Magic has resulted in this spell, which will allow me to enter the consciousness of a willing creature. A grievous invasion of privacy that I couldn't and wouldn't force on even my hated enemies."

The stallion kept his distance as the silent question hung in the air. He gazed at the strand of magic waving in the air above the table. She could feel his magic probing hers, validating her claim and learning from her in equal parts. It sent a pang of painful familiarity through her heart.

After what felt like minutes, he approached and sat down. "What do I have to do?"

. . . . .

Celestia felt herself falling. Falling without wings or magic to catch her. Falling without an end in sight.

It was why she dubbed this spell "Memory Dive."

The first time she cast this spell was in the trusted company of Starswirl the Bearded.

The second was with her sister shortly after she recovered from the Nightmare.

Now, its third ever use in 3000 years was put upon an enigmatic fusion. Another strain of magic that hadn't been seen in a similar amount of time.

Celestia felt as if days went by, yet her fine-tuned internal clock disproved that. When she was finally standing, she couldn't recall ever landing. She stood in the darkness until it was finally given color.

Perhaps color was the wrong word to use. Celestia was in a hospital wing. Despite being crafted from crystal, the walls, floors, drapes, and beds around her gave off that sterile white color. The only sources of variety were two unicorns who were the room's sole occupants.

A dark gray colt with black mane lain still while a purple coated filly with an arctic blue mane sat beside him. Her head rested on the colt's chest, Celestia could pick up quiet hums of some nameless melody.

"Why must this be what you dredge up?"

The Princess closed her eyes. "The strongest memories are always the ones to materialize first." When she opened them, she was no longer alone. "I'm sorry, Sombra."

Beside her, facing away from the memory and into the black empty, was the Sombra she remembered. His silver regalia wasn't composed of armor meant for war, none of his colors invoked a blood red, and his horn and eyes weren't tainted with Dark Magic. When he turned to look at her, she could see the emerald green eyes of the one that had been her closest confidant, unmatched by any other than Starswirl.

She wasn't meeting the gaze of the Shadow King Sombra, but of just Sombra. "It's good to see you, again."

He turned back towards the darkness. "Bask as you please. It is only by the mercy of this spell that this form has been brought from the brink of nonexistence. By that same mercy, a dear friend will endure her fate a second time."

She couldn't respond to that. Even if she had the words, they would've lodged themselves in her throat.

A groan interrupted the silence. The filly hastily lifted her head to see the colt's emerald green eyes wearily staring back at her.

"R-Ra-Radi-" His voice was far raspier then anypony his age should ever sound. The words refused to leave him without a fight.

"Stop, stop. Please, stop." Her voice was quivering, her blues eyes swollen red. She pulled herself close to the colt, burying her head into his neck. "The doctors tried. They all tried, Somby. They couldn't- couldn't- couldn't-" The filly just repeated the same word, unable to complete her thought.

"Radi... ant... Hop...."

"Stop!" Her voice cracked as she pulled back to look at him. "Teacher said that it'll just make the bite spread quicker!" After her outburst, she couldn't meet his eyes and just sank back into his chest. "I'm sorry. I'm sorry. I'm sorry." Just like before, the filly couldn't help but utter a repeated phrase.

"I... chos... t...."

"You didn't choose this! I went looking around after I found that stupid book. I was the reason Teacher asked you keep me out of trouble. I just had to ignore every. Possible. Sign! And, for what?! Some stupid myth?!"

"I... chose... to."

The filly covered the colt's mouth with her front hooves with more force than necessary. "Stop!"

He managed to bring his hooves to hers, but couldn't move them with any force beyond what gravity provided. After listening to her spiral into another bout of repeated muttering, he eventually moved his hooves to gently cup her face. He gently pulled her close until their horns touched.

All noise quieted as a spark of magic passed from one horn to the other and back again. The pair closed her eyes as she wrapped her forelegs around him and he returned the gesture. The two little unicorns held each other close as if the world disappeared around them.

"I love you, Sombra." She opened her eyes to see that his were still closed. "Sombra?" She shook him. "Somby!"

"Enough of this."

"Somby!" The unicorn filly ordered. "Wake up, right now!" She touched her horn to his, a spark rippled through the colt. "Wake up! Wake up! Wake up! Wake up! Wake up!"

"I said enough."

Another, larger spark of magic surged from the filly. Then another. Then another. Then another. Each more concentrated than the last.

"Celestia, please!"

The memory began to fade and waiver until it cut completely; taking with it the cries of a filly following a powerful and painful cracking sound.

The two found themselves standing in the void. Celestia looked upon the floating, glowing orb that carried the unfortunate scene away. Sombra still stared into the darkness, a hoof resting on the protective brace he wore around his neck.

Without a word, Celestia slid over to wrap both wings and forelegs around the other pony. He didn't rebuke her, nor did he accept the embrace. He refused to meet her gaze and didn't make a single noise, but she could feel the occasional tremble.

There was a long silence as more orbs began to drift around the darkness. When they passed by, the Princess glanced, but dared not touch. In their glow, she saw simple images that gave her context to each one.

A younger version of the filly holding fiercely onto the colt of equal age as she stared resolutely at a large, light pink unicorn mare. Two nuns watching on in slight horror.

The two ponies were sitting at desks in a small, private library with that same mare serving as a teacher. The colt was scribbling something in his notebook and didn't seem to mind that the filly was using his shoulder as a pillow.

The filly was on a stage, reading a story while a nun performed a puppet show. The colt looked on from a bit of a distance as he hauled a cart, a small smile gracing his lips.

The same library from before was devastated. The teacher hugging the colt tightly as they both cried into each other. White bandages around his neck stuck out against his dark gray coat.

A battle raged within a cave system as a full battalion of armored guards laid waste to a collection of large snakes with rhinestone fangs. The colt was in the thick of things, his horn aglow with some of the most potent Combat Magic a pony would ever see.

The colt, now a stallion, laughed alongside a few friends. Their attention focused on an orange pegasus walking away dejectedly from a rather irate looking barmaid.

The stallion was in full armor as he kneeled before the teacher as she sat upon a throne. Celestia thought glumly that she looked a bit thin. She never had the pleasure of meeting Princess Amore. From all she's seen and heard, the mare was a just ruler that Celestia would've been proud to work with and was a fellow specialist in Light Magic. In addition, she was one of the few unicorns that had mastered the ability to slow her aging with magic.

But there were limits to what a spell like that could do.

Sombra's hoof reached out and touched the next memory before she could see it. They were brought to what Celestia recognized as the Crystal Palace's throne room. The normally ornate windows were blocked out, the darkness that resulted was weakly fought off with torch and candle light. A circle of ponies hovered around a table in front of the throne. They each pointed and shouted at different parts of a map, their voices creating a cacophony of noise that she struggled to understand.

Doors slammed open to reveal the stallion, marching swiftly toward the group. His plate armor was spotted with numerous scratches and dents.

"Captain!" An orange pegasus stood at attention and saluted. The others quickly following his example. "Thank the heavens you could make it so soon."

The stallion growled and removed his helmet. "I didn't abandon the front line for formalities, Sentry. I need an explanation now." He slammed a piece of parchment on the table.

"Sir." Sentry at eased and took a shallow gulp. "I'm afraid it’s exactly what's on the tin."

"You mean to tell me that in our most dire moment, our Princess has vanished without so much as a trace of magic?"

"Yes, sir." He nodded solemnly. "A week's worth of search and investigation of both the physical and magical nature has resulted in nothing. She was last seen in her bed chambers that night and was missing the next morning. The guards outside her door had nothing to report."

The stallion narrowed his eyes and looked upon the group. Each of them crumbled slightly under his glare, but remained resolute, not a hint of subterfuge or evasiveness in the slightest. Then, several of them quickly made their way to his side as his stance wavered. They assisted him to a spot at the table as the stallion's facade of indomitable strength broke for just a moment.

"Tha- that just cannot be."

"We wouldn't believe it ourselves if we had not exhausted every other possibility."

"Do they know?"

"The Princess' whereabouts have been questioned. Since the griffon's first attack, she's made consistent public appearances. Her sudden absence has left many to assume that the tide of the war must have shifted. An official statement from the Crown has not yet been made."

"'The Crown?'" The stallion scoffed. "Now, who would that be? Amore never declared a successor and... left no heir."

Sentry hesitated before exchanging eye contact with the others.

One spoke up. "At the time of our founding, back in the era of the Queen's Rule, it was decided that, during times of war, greater powers and domain would be granted to the Guard. Particularly, its Captain would hold sway only superseded by the Crown themself."

Another followed. "Our Princess took on many a protégé. Without fail, every single one of them has become legendary figures within our culture. Somepony so close to the Princess would be ideal in carrying out her reign."

A third added her thoughts. "With these times especially, a ruler who has shown the ability to prolong their life through the use of magic would also be ideal. They would be able to steer our nation for centuries to come."

They all stood at attention with eyes on the stallion. From his seat, he stared back with visual confusion on his face that was quickly melting into realization.

"We have all come to an agreement." Sentry cleared his throat. "There is no better pony for the role. There is not one living today that would uphold the Crystal Empire and the lives of her subjects with as much care and precision. I have proudly served as your second in command and would gladly continue to do so as captain of your guard."

Like before, the pegasus performed an action. Like before, the rest followed suit. Unlike before, they were not saluting and paying resects to the Captain of the Crystal Guard. This time, they were bowing and pledging fealty.

Celestia found her gaze wandering to the Sombra beside her, who had his eyes closed in resignation.

"All hail, the Crystal Empire. All hail, Prince Sombra!"