Another Way
The Elements of Harmony blasted light at Twilight, causing her to disappear.
"Ugh," Twilight moaned as she opened her eyes, "What happened?"
Twilight was chained to the wall of a dimly lit dungeon. She looked around the best the she could but couldn't see anyone. She tried to use her magic to break the chains but found that her magic was being blocked by a ring on her horn.
"Is anypony there?" Twilight yelled at the top of her lungs.
A door opened on the opposite side of the dungeon. Twilight squinted at the sudden stream of light until she could see again. She saw Princess Celestia.
"Princess!" Twilight cried out, "Help me get out of here!"
Celestia shook her head, "I'm sorry Twilight, but I can't do that."
"What do you mean?"
"I was the one who put you here in the first place."
"What?"
Celestia didn't answer. Instead, her horn glowed golden for a second and a table covered in tools appeared.
"Princess!" Twilight yelled, "Why am I here?"
Celestia picked up a short knife with a hoof and giggled a little bit.
"What's so funny?"
"Sorry," Celestia answered, "I was just remembering the first time I used this particular blade. It was given to me by the same unicorn I first used it on. But I might just save it for later." Celestia pulled out another knife. This one was about six inches long with intricate carvings on the blade and a slightly curved hilt. "This one was given to me by the ambassador of one of the Minotaur clans."
"Why do you have those here?" Twilight asked. Celestia just took the knife and made a long cut on Twilight's cheek, drawing blood. "What did you do that for?"
"Do you know how betrayed I felt when Luna became Nightmare Moon?" Celestia said, "And do you know how betrayed all of Equestria felt? I swore that an event like that would never happen again." Celestia put her face close to Twilight's and licked the blood off of her, causing her to squirm. "Do you wish to know how I planned to stop this?"
Instead of waiting for Twilight to answer Celestia continued to speak, "I found a spell that allowed me to drain the energy of powerful Unicorns. I began to secretly drain Unicorns who I found to be a potential threat." Celestia slashed at Twilight, creating a shallow cut on chest. Twilight cried out in pain and Celestia began to speak softly, "Don't cry my little pony. This is meant to be fun."
Twilight squeezed her eyes shut to try and get rid of the tears that were welling up, "Please stop this Princess. I promise I won't tell anypony."
Celestia shook her head, "I'm sorry, but I can't do that. You are the most powerful Unicorn I've ever seen. If I have your power I might be able to never need to hurt any more Unicorns. Don't you want to keep future ponies safe from harm?"
Twilight slowly nodded, "But there must be another way."
"You're not the first to have said that Twilight. Perhaps a millennia ago I would've agreed. But now, I actually quite enjoy doing this. Perhaps if you hadn't finished that spell you wouldn't be in this."
"What do you mean?"
"That spell was a test to see if you were ready. I've done many like it over the years."
Celestia raised her knife and slowly began to cut Twilight's upper right leg all the way down to her belly. As she went Twilight began to cry.
"Everything will be alright my most faithful student."
Celestia cut down Twilight's other leg before turning her knife to Twilight's lower legs. She used her magic to pull Twilight's leg away from the wall and placed her knife on the side, just deep enough to draw blood. Then she cut upward, winding the knife around Twilight's curved flank until it met the place where her other cuts intersected.
Celestia did the same to Twilight's other leg and stopped cutting as her student tried to form words.
"W-what about m-my friends?" Twilight sputtered.
"I already have that planned," Celestia replied, "After the Changeling invasion there were a couple prisoners left. I forced one to transform into you and I replaced all of its memories with yours. In a couple of days 'Twilight' will be sent on an assignment to the Gryphonia. Her ship will be lost at sea and that will be all."
"But what about Luuuuuuna," Twilight screamed as Celestia licked the cut on her left hind leg, causing a strange mix of pleasure and pain to rack her body.
"Sorry about that," Celestia wiped a few drops of Twilight's blood off of her white coat, "I can see why there are so many carnivorous races. But about your question, Luna doesn't know. She doesn't come down here and we made an agreement long ago to not walk in each other's dreams. Now, can you please be quiet. I am trying to enjoy this as much as possible."
Celestia continued to make cuts on Twilight's skin, even as the latter squirmed under the knife. After about ten minutes of this, Celestia licked Twilight's wounds one more time before saying, "I believe it is time to begin the main part of the spell."
Celestia picked up the knife from before. It was a larger version of a surgeon's scalpel.
"First, I must obtain the ingredients," Celestia said, "I need to obtain the mana glands of the victim."
Twilight painfully cringed, and not just because Celestia called her a victim. The mana glands of a unicorn were filled with the magical energy of their bodies. These glands were also found in the bodies of Earth ponies and Pegasi and were used to access the ambient magic of the planet and either fly or use their enhanced strength. Ponies usually only had one mana gland, but Twilight happened to have three.
Celestia's horn glowed and three spots on Twilight's body began to glow. She used the knife and cut into the right side of Twilight's belly, which would have caused her to scream if she hadn't lost her voice from the least ten minutes of crying.
Once the hole was deep enough Celestia used her magic to pull out a small organ that looked like a bit-sized carrot. Celestia quickly cleaned it with her magic and placed it on the table beside her tools.
Twilight began to bleed greatly, but Celestia didn't panic. The Princess just placed her horn on the wound and it healed.
"I wouldn''t want you to bleed out, mana glands can only be harvested from a living body." Celestia said. "This next part might hurt a little bit more." She placed a hoof in Twilight's mouth, causing her to taste her own blood. Celestia used her magic to manipulate the blade into Twilight's right leg, right into the cutie mark. She used the same procedure as she did with the first gland and wound and removed her hoof from Twilight's mouth.
"Just one more gland," Celestia sighed, "And it's in the same place for every Unicorn."
"Please Celestia!" Twilight whispered, "No."
"I'm sorry Twilight, I truly am. But it is time for the final gland."
Celestia pulled back and grabbed a bone saw. She began to cut through Twilight's horn, causing magical energy to be released violently. The Unicorn's body began to spasm as her power left her in a long stream. Celestia managed to get all the way through the horn and pulled it off. She removed the gland from within the stump and Twilight's body went limp.
"Princess," Twilight's whisper was barely audible, "Are you there?"
Celestia released the chains and Twilight's body fell into the princess' waiting hooves.
"I'm here my faithful student," she whispered into Twilight's ear.
"I forgive you."
A tear fell from Celestia's eye. "Thank you."
Celestia listened to Twilight's breathing until it eventually stopped. The Alicorn gently placed Twilight's body on the ground, tears streaming down her face. She went to the table and levitated the three mana glands into the air. Her horn glowed brighter and the glands turned into golden light and were absorbed into Celestia's horn.
She went back to the body and teleported it, along with herself to the farthest back part of the gardens. She placed Twilight in a hole she dug earlier and filled it in. then, she sat down in front of the grave.
"So you finally did it," a voice said. Celestia turned around to find Discord staring at her.
"What do you mean?" Celestia asked.
"While I was in stone I could see everything. I saw every murder you did. But I never thought you would kill Twilight. She was like a daughter to you."
"I know," Celestia began to sob for a moment and then stopped, "Discord, I want you to bring her back."
"What?" Discord held his claws in the air, "I am not going to perform necromancy. Even I'm not that crazy!"
"Just for five minutes. Please. I want to apologize."
"So," Discord created a cloud and lied down on it, "The great killer of dozens wants to apologize to a victim."
"Just do it Discord. I can still use the Element of Magic and if I tell Twilight's friends that you killed her we can use the Elements on you."
After a minute Discord sighed, "Fine." He snapped his talons and Twilight appeared. Her body moved slightly as she breathed. "I'm getting out of here to avoid the storm that's coming." He teleported away.
Celestia picked up Twilight and held her close, "I am so sorry for doing that."
"I already forgave you Celestia," Twilight replied.
"I know, but just let me hold you."
As Celestia held Twilight she didn't notice that her student's eyes turned completely black. Twilight opened her mouth and revealed two rows of razor sharp teeth. She bit into Celestia's neck, causing her to scream in pain.
"Twilight?" Celestia looked at her once faithful student in fear, "What are you doing?"
Twilight swallowed Celestia's blood and said, "You said that killing so many ponies would save even more lives." Twilight grinned, revealing her bloodstained teeth. "I have found a better way."
Celestia screamed as she was torn apart by the being that was once Twilight.