“And how, exactly, am I supposed to assist in this ritual?”
In the crystal caverns beneath the growing city of Canterlot, Princess Celestia sat on a moderately uncomfortable rock while Arcane Catalyst drew increasingly complex runes onto the floor of the cave, in a circle around a deep indent not unlike a cauldron. It was even filled with water. He stopped his setup and carefully moved to Celestia, careful not to step on any lines. It had been five long years since Arca had proposed his plan, and finally he was ready.
“Well, Princess-boss, I have gone through several texts, including those ‘forbidden’ ones you managed to get me, and according to my working theory, creating a philosopher's stone is incredibly simple. ‘But why doesn't everypony have one?’ you may ask. Good question! See, creating it is easy. It's STABILIZING the stone where the issue lies. See, when the stone is used, it uses up some of its energy. But that power also holds it together. Without the power to stabilize it, all you have is a massive explosive capable of leveling a building, and…”
“Is that what happened to your little lab a few months ago?”
“Yes, actually! It was very informative even though I was in the hospital for a few weeks. I'd gladly do it over again. Anyway, from some of the more… dark texts you have given me in your desperation to get your sister back… Oh! Sorry, I didn't mean to sound insulting or something.”
Celestia laid a hoof Arca's withers sympathetically. “I understand what you meant, Arcane. Trust me, I will admit I want my sister back, but make no mistake: I let you read those books because I trust you to find a safe and reliable answer.”
“Well, have I got the answer for you!” he beamed. “As I was saying, most dark magic texts imply that the only thing strong enough to hold the stone together is soul energy, but I don't think they are right. It says older ponies’ souls always have less power remaining than younger souls. Thus, I theorize that it is not the souls themselves, but their time! Their lifespan! The more years you have left in you, the more time-power! It might also explain why most ghosts in local legends didn't pass away of old age, as anypony that dies of old age has likely used up all that energy living their lives!” Arca paused, catching his breath from his impromptu lecture.
“Oh, I get it. You need me to be the life force, right?” Celestia inquired. Arca nodded, still resting. “That makes sense. Since Alicorns are immortal due to our innate connection with the force of harmony, I should be able to share some of that time-power without dying, since infinity minus anything is still infinity!” That got Arca to applaud by stomping his hooves excitedly into the stone beneath him.
“Yes, yes! Exactly! You can stabilize the stone all by yourself, and it won't even hurt you! Well, beyond the blood sacrifice…”
“Wait, did you say-” Celestia didn't get to finish her sentence as she felt her barrel become very wet. Looking down revealed that Arca was just levitating water into it.
“Kidding! Only kidding. There's no blood sacrifice or anything. Well there is, but I already did that and BOY am I dizzy from blood loss!”
“Dare I ask?” the princess inquired.
“Fifty gallons over the course of five years, all under stasis spells in those buckets over there.”
“Arcane… You could have asked, and I would have helped you or set up a blood drive, or something. You're starting to sound a little crazy.”
“Eh, you need to be crazy to stay sane some days. Besides, I didn't want to drain the treasury gathering all the materials. Blood was the least of my concerns; I needed hydra scales, energy crystals, the core of a timberwolf…”
“I don't recall ever getting you those, Arcane.”
“I hired mercenaries to help me get them. And you wouldn't remember hiring mercenaries either, since I did it myself. My potion shop's doing pretty well, so I figured I'd take the load off your withers. Now come on! I don't want three hundred thousand bits worth of planning to go to waste! Give me a shaving of your horn, a primary feather of your wing, and some hoof clippings! The power of the three pony tribes should allow you to form a connection with the stone and channel your time energy to it.”
Celestia hoofed over the three requested ingredients, and Arca finished up the runes before beginning the ritual. Pouring in the ingredients, he began mixing the brew while channeling magic and chanting words of a forgotten tongue. Before long, Celestia noticed the red blood in the water was appearing to condense into a single area. The middle of the pool. As Arca continued, she noticed the form of a small pebble amidst the red, no larger than a strawberry. She grasped at it with her magic, and found a metaphorical hoofhold with ease. “I have a grasp on the stone, what do I do now?”
“Wait, you weren't supposed to grab it that early, Princess-boss! Let go before-”
Celestia let out a scream of agony as she felt a force RIP at something inside her. It was pulling… something, out of her, but she couldn't identify what! It was the most pain she'd known in her life, and could only hear a few words from Arcane as if he were miles away.
“--------oss! ---'t pan---! -'l- s--p th- --------!”
Arca flew into a panic as soon as he realized what was going on. The stone was trying to rip energy from Celestia's wellspring of immortality to stabilize itself! It was so strong he could SEE the flow of magic from Celestia to the stone. But then it moved, seeming to come from nowhere as the stone drew power from the omnipresent force of harmony istelf! This was bad, absorbing that much energy without a regulator would cause a chain-reaction that could level the entire mountain!
“Princess-boss! Don't panic! I'll stop the reaction!” Arca didn't even think. He did the only thing years of working as an alchemist trained him to do: when all else fails, rely on your instincts.
So naturally he dove into the water, getting in the way of the beam and proceeded to shatter the stone with a well-placed kick.
And then there was an explosion.
Arcane regained consciousness slumped up against the wall of the cave. Celestia was there, too, having been freed from the stone's attempted soul stealing. She was tending to his wounds, thankfully none the worse for wear from the fiasco. “Ow… my head. What… happened?”
“Looks like you made a philosopher's stone… but not the way you intended,” Celestia replied, pointing to the finished product.
“And that is the story of how I got my cutiemark,” Arca finished, lifting the back of his lab coat enough to display the stylized red stone with a spiral pattern emblazoned on his flanks. “I won't bore you with the details, as you'd need a degree in advanced theoretical magic to understand it, but my will to stop the reaction coupled with my desire to only take what I needed of Celestia's infinite life force fused the stone with me and altered the energy flow. I am the philosopher's stone, my talent is alchemy, and I don't age because I too draw power from whatever infinite harmony energy or whatever Celestia and all the other alicorns use to stay ageless. It also caused the tips of my mane to turn orange and yellow, like the sun. She didn't mind… in fact, she asked me to use the extra years I gained to find a safer way to try again! But, she did order me to wear my lab coat in public to hide my new mark so nopony would know I actually succeeded in crafting the stone. She rescinded it after 50 years, but by then it was a habit of mine, so I kept it on.”
Juniper and Meadow took a long minute to process this. Juniper spoke first. “That's… a lot to take in, Arca.”
“I know. Maybe some cookies will help! Are they done yet, are they?”
“You never change, do you Arca?” responded Meadowbrook. “I'll go check on them.”
“Woohoo!”