The sound of claws tapping against the crystalline floor echoed through the halls of Canterlot Castle as a lone figure made it's way through the darkened halls. If one were to look closely, they could make out the hooked beak of the griffon slinking through the darkness of the castle walls. It nearly tripped over a chip in the floor, and let out a deep groan. "Curse these old bones..." It spoke, in the gravely and aged voice of an old griffin.

He made his way to a window, and gazed upon the night sky. His face was angular, and his beak orange and weathered and hooked at the end. His catlike green eyes furrowed as he looked to the moon, fractured across the sky. His gaze turned downward, to the land below. Off in the distance he saw Ponyville, or at least what remained of it. A blackness like ink had overtaken the town months ago, and despite the best efforts of her majesty Princess Twilight Sparkle's council, they had made no progress in stopping the darkness from spreading. In the past week it had reached Canterlot and overran the city. As of now it moved upon the castle's doorstep. As far as he knew, only three survivors remained.

As his gaze moved to the perimeter he could see the shadows swirling and bubbling in a disgusting manner. It wasn't until the clip-clopping of hooves broke him from his thoughts that his eyes again moved to the moon above, though he did not look back to see who was approaching.

"Princess Twilight wishes to see us in her throne chamber, Osirus."

The griffon nodded, and looked back to his sudden company. She was a magenta Alicorn, with a silver mane. A single, thick braid hung from the back of her main, and two smaller braids wrapped around the base of her ears. Strands of teal streaked through her hair, doing well to compliment her blue eyes. "Very well Opaline. I will be joining you shortly." The Alicorn shook her head, and motioned for the griffon to follow. "I'm afraid not. She requested we show up now."

"It is important then?"

"We can only hope Osirus." The two passed through an archway, and into another hallway, this one lined with the armor of decades of worth of warriors. Osirus felt a pang in his heart as he looked upon them. "The Lunar Guard....it's hard to believe the army I once led...has been all but wiped out."

Opaline nodded, and approached the end of the hallway where a glass display stood, as well as a fork in the path, with the hall leading both left and right. "They have been badly beaten many times before, but to this extent?" She looked to the display, a solemn gleam in her eyes. "It truly is hard to believe..."

Osirus gazed upon it as well, and nodded. Inside was a set of armor, fit for a much younger griffin. The plaque below it was smudged, and in the darkness of the hall he was unable to make out much of what was engraved into it. What he did make out was a day, dated back to exactly fifty years ago. "Let us make haste Opaline. Our princess did request as such." He turned to the right, and never looked back. Opaline followed suit, though she did a quick turn, giving the hall a solemn look.

The trip to Princess Twilight's throne room was silent, and as Opaline pushed the door open with her magic, Osirus noticed a strange lack of the princess herself in the marble room. "That's strange, she was here not long ago."

"When did she summon us?"

"I'd say around fifteen minutes before I summoned you."

Osirus raised an eyebrow. It wasn't like Princess Twilight to up and disappear, especially immediately after summoning two of her inner circle. Something strange was afoot. As he walked towards the throne he took some time to study the stained glass windows. It was a hobby of his, gazing upon artistry and symbolism around the castle. He was a historian in his old age after all. Reaching the throne before him, Opaline found a page laying on the seat of the throne. Curious, she picked it up in her magic, and began to read it out loud.

"To my dear friends and most faithful students, Opaline and Osirus; I suppose I should apologize for my sudden disappearance. I'm sorry I haven't had the time to discuss this with either of you, but I may have found a solution to saving Equestria. Before I became an alicorn, when I was still Princess Celestia's student, I received a visit...from myself, one week into the future-" Opaline was cut short as Osirus let out a sigh.

"She truly does love that story."

"All of us love that story. As I was reading; I received a visit from myself one week into the future. I'd thought she'd come to warn me of some disaster that was going to take place, but after dealing with the weeks events, I traveled back one week to tell myself not to panic, that nothing would happen. I've always been of the opinion that time travel is nothing to be messed with, but I've finally made my choice. I'm going back several thousand years into the past to the early reign of Princess Celestia and Princess Luna. From there I'll have enough time to find out what's causing all of this, and I can stop it before it starts."

Opaline and Osirus both glanced at each other worriedly, and Osirus nodded to continue reading. Opaline did so.
"Opaline Arcana, in all of my time ruling, you have been the most gifted, most powerful student I've taken under my wing. Ever since we found you in Ponyville all those years ago and showed you how much more you can- blah blah blah, goodness she gets so mushy sometimes."

"Agreed."

"Ah! Here we go; in the event that Canterlot Castle comes under attack, or even an equal emergency, open a time portal to the one thousandth Summer Sun Festival since Nightmare Moon's banishment. That will act as our rendevous point. I hate to leave Canterlot Castle unguarded, but your safety is far more important. Your mentor and friend, Twilight Sparkle."

Osirus nodded; "So we are the last guard of Equestria now?" He furrowed his brow. He trusted Twilight, he really did, but leaving them here as the last stand for a world on the verge of collapse? He saw Opaline reread the letter, likely as confused as he was. "Open the time portal." He demanded.

"What?"

"Open the portal." He repeated. "As she said, our safety is far more important than this blasted castle. That darkness is-"

"We're the last of-" The griffin could see the tears forming in Opaline's eyes.

"That darkness is on our doorstep Opaline! We need to meet with Princess Twilight now!" Osirus let out a sigh. "We need to go too Opaline. I'm sorry, but Canterlot Castle will not last longer, and unless we leave we will fall with it."

Opaline looked away, but nodded as her horn began to glow. Osirus let out a huff. "I am sorry Opaline...I..." Off in the distance a screech could be heard, and Opaline and Osirus both looked to the throne room door in horror as it burst open, a dark ooze seeping through the doorway ever so slowly. "Hurry Opaline!"

The Alicorn in question nodded, readying the spell that would open the time portal to Ponyville.

The shadows began to approach them faster, forcing the two to back themselves closer to the throne. Opaline sealed her eyes shut and and pushed herself as close to the throne as she possibly could, and in the darkness of the doorway Osirus could make out a silhouette. It's hand reached for the side of the throne room's door frame. As it stepped forward he could see it clearer, and it stood on two legs, with broad shoulders and horns like a minotaur. Osirus thought he could see wings, but he couldn't quite tell for sure. "Opaline-"

"GOT IT!" She shouted, a flash blindering Osirus and herself. Levitating atop the seat of the throne stood a swirling portal glowing a bright teal hue. As Opaline made an attempt to climb to the portal, a tendril lashed out at her from the darkness, wrapping itself around her barrel and throwing her to the side and knocking her out before the bipedal figure made a dash towards Osirus. As nimble as he was in his youth, he was now older and far less athletic, and the figure quickly wrapped it's claws around his neck. Gasping for air, the figure brought him face to face with itself. It spoke in a venomous tongue, its speech wavering but never faltering, it's voice unnatural and gravely. "You cannot stop what is coming."

Struggling for breath, Osirus could not respond as smaller tendrils emerged from the figure's wrist and began to wrap around his neck before covering the rest of his body and seeping in. The last thing Osirus would remember is the feeling of being crushed by an endless abyss.

As Opaline Arcana finally awoke, she watched as Osirus made his way through the time portal. She let out a gasp, begging him to wait to no avail. As the portal closed she let out a cry. She would be left here to be consumed, betrayed by her best friend. She wouldn't live long enough to wipe her tears away before the darkness consumed both her and the rest of the castle.

Thus ends the story of Osirus Cecil and Opaline Arcana.

Author's Note

Interludes are canon plot elements I promise.