Original Link:
https://docs.google.com/document/d/1R6HiPVvPNvGu62c6x7_IHfQqYxK6XnKkfd5d7Dj05Hk/edit

“Here! Here it is! Red-eyed monsters took purple pony in there! Rufus is sure of it!” the small brown diamond dog announced.

“Grātiās tibi agimus, Rufus. You have kept your part of the deal, so we will keep ours as well,” Obsidian thanked, then turned his head to Rarity.

“A-are you sure we can trust his word?” she wondered, holding a large bag of gemstones.

“C’mon, Rarity,” Applejack insisted.

“Ugh, fine... Goodbye, my pretties...” the fashion diva stated before handing the bag to Rufus. He instantly opened the bag and checked the quality of the gems.

“Rufus likes making deals with cursed ponies!” he stated in satisfaction after he finished.

“This better not be a dead end, diamond dog!” Rainbow Dash threatened.

“No... this is definitely not a dead end... See this?” Derpy Hooves asked, pointing in the tunnel ahead of them.

The ponies could see how, after just a few miles, the color of the darkness in the tunnel turned from black to red.

“Tartarus... of course...” Derpy stated again, gulping hard. “Of all the demon strongholds, they just had to take her to the most infamous one...”

“Keep it together, apprentice. Yes, Tartarus is maybe the most populated and dangerous demon stronghold of all. But it also means we get additional support. Am I correct, Cerberus?” Obsidian questioned, looking up. The massive three-headed hellhound barked in confirmation.

“Oh my goodness. I just hope we are not too late,” Fluttershy worried.

“The demons went through the effort of kidnapping her and making it as difficult for us to follow as possible. If they just wanted to kill her, they had their chance. They need her alive, id nōn dubitō,” the black stallion stated.

“Yeah, girls! Keep your little heads up! We didn’t leave Ponyville and went searching for Twilight for a whole week to give up now! We can do this! We can save her!” Pinkie Pie motivated.

“Gee, Pinkie. I’m a reaper and you have more courage than me!” Derpy stated, causing the party pony to giggle.

“Well, Rufus be going now. If ponies come back alive, Rufus likes to make more deals!” the diamond dog announced, then turned around and walked away with the bag.

“We all better prepare for this,” Obsidian spoke and started unpacking the bag he carried with him.

Among the items he brought for this journey were several steel horseshoes, nails, rune pendants, enchanted stones and potion bottles. The black stallion then used his magic to hand out his supplies to the others.

“Applejack, Rainbow Dash. These are for you,” he explained while offering them both a set of horseshoes and nails. “Nailing them in your hooves may hurt, but will provide critical protection and power to your punches and kicks.”

Applejack and Obsidian started mounting theirs immediately. Derpy brought her own supplies and joined them. Rainbow Dash, though, had her concerns about wielding these metal improvements.

“No thanks, O. They would only slow me down,” Rainbow Dash explained.

“As you wish,” Obsidian responded while wrapping a rune necklace around his neck by magic and handing another over to Rarity. “This one is for you. It will increase the effects of your spells.”

“Oh! Why thank you most sincerely! With only a bag full of diamonds, I felt a bit unprotected,” Rarity thanked.

“Sadly we can not afford to be slowed down by full body armor. This needs to be as fast as possible. Pinkie Pie, Fluttershy. Are you sure you do not want any equipment?” the black stallion wondered.

“I got two whole bags of supplies, silly! Keep the rest for yourself!” Pinkie responded.

“As long as I stay close to you, I don’t need anything else, my love,” Fluttershy explained.

“Bene,” Obsidian replied, then turned to Derpy and handed her one of his potions. “Drink this. We will need all our strength to make it.”

“Is that some kind of stamina potion? Can I have one?” Rainbow Dash wondered.

“No, Rainbow. I highly doubt you want to drink this,” the black stallion answered while opening a bottle himself and drinking its red content. Derpy instantly jumped up in shock over his actions.

“Elder Obsidian! Have you lost your mind to drink pony blood in front of them?” she exclaimed.

“They already know, apprentice,” he replied calmly.

Derpy’s eyes jumped between the keepers of harmony. Although this statement put a light expression of disgust on their faces, they all remained calm and nodded in confirmation.

“You are bending the rules, Obsidian. Mistress Celestia will not be happy about this,” the gray mare concluded with a sigh.

“Hey! Don’t you snitch on our friend, okay?” Pinkie insisted.

“Ugh, okay. I’ll keep my mouth shut this time, since we already are in a crisis... And I really need a drink myself...” Derpy agreed and emptied the bottle Obsidian gave her.

“So, what’s the plan, Obsidian?” Applejack wondered.

“We all need to stay together. The five of you will lead the troop. Your task is to push forward and keep an eye on your surroundings. Run constantly and only stop if there is no other choice. Leave most of the fighting to Derpy and me. We will provide protection from the sides and above. Cerberus will cover our backs and fend off anything that is approaching from behind,” the reaper explained.

“And another thing... Each demon stronghold has a stronghold warden. A special, high-ranked demon who only exists to protect the stronghold. It is pretty large, but can hide inside the walls and ceiling. We don’t have the time to fight it, so try to spot it as fast as possible. We need to distract it. If it cuts in our path, we have no option but to cancel the rescue,” Derpy added.

“Any questions remaining?” Obsidian asked.

“None that I can think of right now,” Rainbow Dash responded.

“Good. Get ready, everyone,” Obsidian concluded.

With that statement, the ponies, reapers and the hellhound got into position. Applejack threw one last concerned glance at her hind legs.

“Bucky McGillicuddy, Kicks McGee. Don’t fail me now,” she spoke to them.

---

Running into the tunnel Rufus discovered made them feel like disregarding all their instincts. The sensation of dread grew stronger and stronger the deeper they went in. As they approached the red demonic darkness, not even a light spell could break through the thick, fog-like mass that filled the air. Although they could hardly see where they were going, they noticed that the structure of the ground below them started to change. What at first was solid stone became something a bit softer and made a different sound when walking over it. A kind of clattering. It took them awhile to realize that this sound was caused by countless bones, getting more and more the deeper they went inside.

Finally, the group saw the first two pairs of glowing red eyes, staring directly at them. Immediately, the demons seemed to try to close the path before them by pushing two humongous stone slabs together. Obsidian rushed ahead, throwing himself between the slabs and trying to push them apart again. Although the black stallion was very strong, he couldn’t handle the strength of these two gatekeepers for long.

“Cerberus! Break through!” Derpy commanded.

Instantly, the hellhound barked in confirmation, jumped over the group and rammed the stone slabs with all his three heads at once, sending them flying. Obsidian immediately assaulted the gatekeepers and consumed them.

“Rarity! Light, now!” he spoke as soon as he was done and covered his eyes using his cloak.

The fashion diva then lifted a diamond out of her bag and used it to cast a strong light spell. Amplified through the rune pendant she was wearing, the spell was strong enough to break through the red darkness, providing the group a brief glimpse inside the stronghold. It was an enormous hole, divided by three platforms and a huge pillar on the middle one. Everything seemed to be made out of bones, covered in a thick red slime. Though only a minority of all the victims’ remains were visible. Black bodies and red eyes popped up everywhere. On the walls, on the ceiling, in the air. An uncountable amount of eyes were looking at them.

“Holy Moly! I don’t think this was a good idea!” Pinkie shouted.

“No, we had to know where to go to. We need to get down, keepers! I bet they got her as deep into the stronghold as possible!” Derpy explained.

“The gatekeepers wanted to prevent us from entering. That means she is definitely here,” Obsidian stated while flying back in position.

Now that every last demon in the entire stronghold knew about their presence, it became suspiciously silent. The demons were in their element. Inside the red darkness, only the reapers could sense them approaching. While a few lower ranked demons were chasing after them, Obsidian sensed something rapidly approaching from above.

“Derpy! Wraiths!” he announced.

The gray mare instantly took an enchanted stone out of her supply bag, drew a banisher circle on it and lifted into the red. A few moments later, she returned.

“Done,” Derpy stated.

A good minute passed while more and more demons arrived, trying to sneak up on the group from behind. Cerberus, though, could push them to distance.

“Darnit! I don’t see anything! Where is it? Where’s the warden?” Rainbow Dash questioned.

The keepers of harmony kept looking around in search. Suddenly, Applejack realized with a shock that there was a pony-sized red eye in the ground, not far away from them.

“It’s below us!” she shouted.

Obsidian gained a troubled expression. He summoned his scythe and rammed the blade in the ground below them. A deep, loud moan came from it and huge black tentacles covered in red slime and eyes grew out of the ground.

“I will distract it! Keep running! Get down as fast as you can!” the black stallion announced.

The others didn’t have much time to argue as a large swarm of demons was approaching them. Rarity used another diamond, this time as an attack aimed to the swarm. The gemstone turned into a powerful beam of light, piercing through the demons and confusing them for a moment. Just enough time to make it down the ramp of bones to the first sublevel.

---

Fighting their way through Tartarus proved to become the most difficult task the ponies had ever been through. Pinkie Pie used the party supplies she brought to distract the giant waves of demons assaulting them. As the group finally got down to the first sublevel, Obsidian rejoined the group with several bleeding cuts over his face and chest.

“Gosh! For a moment, I got worried about you! What happened to the warden?” Derpy wondered while running.

“I managed to lure it far in the back. Hopefully, it will be unable to catch up,” Obsidian responded.

Suddenly, the demons started whispering again. The keepers of harmony slowed down, listening to it with a fear filled expression.

“No, no. That ain’t true! We didn’t let Granny down! She wanted to go!” Applejack tried to reason.

“Don’t listen to them! Ignore the whispering! They just want to demotivate us!” Derpy explained.

The mares tried hard to ignore the cruel, very personal words of the demons and increased in pace again. As they came closer and closer to the pillar, the demons changed their tactic. Instead of attacking the group from all directions, they now formed a massive wall right in front of them. Avoiding a full combat would not be possible anymore. If they wanted to proceed they had to fight their way through the demons.

“Cerberus! Fetch!” Obsidian announced.

The hellhound made a big leap right into the mass of demons, punching, kicking and biting them. As the black creatures focused on assaulting Cerberus, an empty space formed below him. The group had to get there in order to be able to guard themselves.

Derpy and Obsidian rushed ahead, slicing a path through the demons. The five mares followed up quickly, narrowly making it below the three-headed dog before the gap filled up with demons again. While Cerberus did his best to fight back the masses of demons, the rest of the group battled those who made it below the hellhound. They tried hard to break the group apart and lure them away from each other.

A massive battle broke loose. Obsidian focused on getting the main attention of the demons. Fluttershy used the combat techniques the black stallion taught her to support him. Derpy started drawing a large rune on the ground. Pinkie Pie threw everything she could pull out of her bags at the demons to confuse them. Rarity turned one diamond after another into light spells, effectively supporting Cerberus in fending off the masses of black creatures. Rainbow Dash used her agility to dodge getting attacked herself and supported the others.

The steel horseshoes Obsidian provided now proved their efficiency. Even though demons can not be harmed physically, the powerful kicks of Applejack knocked them back in the masses. The orange mare focused on holding the group together, supporting those of their group who were about to get lured out.

While Obsidian did all he could to protect the keepers of harmony, he lowered his own guard, giving one demon with two giant bladed arms the opportunity to ram one of the blades through his right hind leg and nailing him to the ground. The reaper remained focused, drawing his scythe and using it to block of the second blade before it could chop off his head.

“Argh... Fluttershy!” he shouted.

The yellow mare instantly turned around. As she saw that he was in trouble, she flew over to him and gave the demon a flying kick.

“Benignē ades,” Obsidian thanked. Even though his leg had been pierced, the reaper ignored the pain and kept on fighting.

“Just a moment more... just a moment more... got it!” Derpy announced, finishing the rune. “Everypony, take cover! Cerberus! Activate the seal of the hellhound!”

This statement seemed to relief the three-headed dog, as he was starting to get a few bad injuries from the countless claws, teeth, blades and nails. As soon as the others stepped out of the rune and duck their heads, he jumped on it and began howling. The rune activated and his collars began to glow. Moments later, dozens of sharp, spiked chains shot out of them in all directions, impaling a large quantity of demons. The chains then retreated inside the collars, trapping all the caught demons inside them.

“This won’t last long! They are too many! We need to get going, stat!” Derpy announced.

“Looks like you caught the strongest ones. Let me take care of this!” Fluttershy spoke.

After months of training with Obsidian, she now gained control over her powers. Fluttershy faced the demons ahead of them and gave them the Stare. Instantly, a large amount of them became paralyzed.

“Get out of the way!” she shouted with a force in her voice none of her friends ever heard before. It was so strong that even they became a bit scared of the yellow mare.

The effect on the demons was much stronger, though. A large amount of low ranked demons flew and crawled away in panic. The rest was unable to move, allowing the group to rush by.

“Good gosh, Fluttershy! Look at them go!” Rainbow commented.

“I told you I don’t need any equipment. I already got everything I need, all thanks to Obsidian,” the yellow mare responded while leading the way.

“Your training really paid off, mea amāta. Now focus, keepers! We are entering their breeding grounds!” the black stallion announced.

“Breeding grounds? How do they breed?” Pinkie wondered.

“Well, have you ever wondered why zombie ponies are so rare to find? Just look,” Derpy explained.

Finally, the group reached the pillar. This, though, was the most horrifying sight of all, due to it being made entirely of undead ponies. It seemed like the demons gathered them and put them here, only to torture them until they grew insane enough to give birth to more demons. The agonized moaning and rotten smell of these thousands of undeads was unbearable, yet they had no time to help even a single one of them. If they wanted to make it out alive again, they had to find Twilight and take her out of this nightmarish place soon.

The only way to keep getting further down was to pass by the pillar. The mere presence of the group was enough for a good dozen of new demons to be born before their very eyes. They instantly rushed down the pillar to attack them.

“Obsidian, another stare?” Fluttershy wondered.

“No. Save your strength,” the black stallion responded.

He then halted, picked up one of his blood potions, casted a dark spell on it and launched the potion at the pillar. On impact, the bottle exploded and due to the curse Obsidian put on it, the newborn demons stopped to stare at the blood for a while. This provided the group enough time to finally make it down to the lowest platform.

---

The demons put more and more effort in stopping the group from proceeding the further they went on the lowest level. By now, Rarity nearly used up all her diamonds. It was clear that it would become a lot harder to push forward when she would run out. Even Cerberus whimpered in pain as his collars started to smoke. The rune spell would break soon. It was then when Rainbow Dash made a very relieving announcement.

“Twilight! There she is! I can see her!” she exclaimed.

The pace of the group increased once more, all of her friends calling for the purple mare. As they came closer, they realized she was running around aimlessly in panic while being chased by multiple small demons.

Obsidian broke out of the formation now, rushing ahead in order to help her. But as he was only a few inches away from her, a long black arm suddenly shot out of the red and pinned him down. More black arms followed, nailing the other ponies to the boned, slimy floor as well. The only two who could keep up a struggle were Cerberus, due to his size and strength, and Rainbow Dash, due to her swiftly dodging the attack. Then, the source of these arms revealed itself. A demon Obsidian and Fluttershy had seen before: Slendermane.

Cerberus struggled heavily to both fight back the approaching demons and Slendermane’s arms. The faceless demon was forced to put most of his focus on immobilizing the hellhound, only using a few arms to chase after Rainbow Dash. She was the only one left being able to do something and she had to act quickly. In only a few moments, they would be overwhelmed.

She decided to put all her strength into flying as fast as possible, dodging the black arms while approaching Slenderman from behind. Although the demon realized this, it was already too late for him to defend himself anymore. He completely underestimated Rainbow’s speed. So, as he turned his head in her direction, she was already close enough to ram him with full speed.

The grip loosened on the group members and all except Obsidian quickly came together again. The black stallion, though, flew over to Rainbow Dash and Slendermane. He knew she wouldn’t be able to get up on her own in time before he would tear her apart.

“Rainbow! Tell the others to run back and grab Twilight! I will take care of Slendermane for as long as I can!” he commanded.

The Pegasus mare jumped back up, saluted to him quickly and followed his order. After she informed the others, the athletic mare flew through the masses of demons as fast as she could. Finally, she reached Twilight, grabbing her and lifting her into the red air. With Dash still holding the struggling purple mare in midair, she rejoined the group. None of them could see Obsidian or Slendermane anymore. Fluttershy became worried, but even more concerning was the fact that the way back up would be much more difficult than getting down. As if this wasn’t stressing enough, Pinkie realized with a shock that her tail started twitching very heavily.

“Something’s gonna fall! Something’s gonna fall!” she shouted in panic.

The group hit the brakes hard, just in time to avoid getting crushed by a huge black mass climbing down from above. The stronghold warden returned and seemed to be extremely furious. It completely disregarded the platforms and just crushed through them in order to get to the group.

The ponies and the hellhound ran the other direction again while getting showered with bones, demons and tentacles. Cerberus did all he could to fight the warden, yet he knew even he had no chance against this demon.

But luck was on their side. Through the warden’s rage, the platform above them collapsed on one side, creating a ramp they could run up. This would only help them escape the warden for a moment though. Suddenly, Derpy had an idea.

“The pillar! We need to knock it over!” she shouted.

“That huge thing? How are we gonna do that?” Rarity wondered.

“I have an idea. Remember how ponies always call me clumsy for breaking things?” she questioned while speeding ahead into the air.

The gray mare tore the rune pendant from her necklace, threw it into the open mouth of an undead pony and then smashed her hip against the pillar in full flight. The destruction rune on her flank and the amplifier rune on the pendant reacted with each other, sending a powerful shockwave through the pillar, followed by a crack that went all the way through. Moments later, the pillar broke in and fell sideways, creating another ramp all the way back up where they came from.

“I just don’t know what went wrong!” Derpy stated mockingly afterwards.

“Derpy, forget what I said last time. You are a genius!” Rainbow Dash complimented.

Now, the demons realized they were about to escape. The entire stronghold focused on reaching the tunnel before them. The group had to run fast, especially because the warden was still closely behind them and the undead ponies in the pillar tried to grab and bite them. Applejack looked around carefully, kicking back any demon that came too close to her. Then she spotted two figures rushing past her.

“Rarity! A diamond! Over there!” she shouted.

“Okay, but that’s my last one!” the fashion diva replied.

One last time, she turned a diamond into a beam of light. As it broke through the red darkness, they saw it hit Slendermane, allowing Obsidian to rejoin them.

“I do believe I owe you a favor for this,” he commented.

“Nevermind it! Just run! Run!” Applejack responded.

The rest of the rescue mission was just a very narrow race back to the tunnel they came from. Twilight still didn’t seem to understand what was going on and kept on struggling against Rainbow’s grip. The warden towered behind them, focusing the group with all his eyes and readying his tentacles to launch them at the ponies. Ultimately, the seal of the hellhound gave in and released all the demons that were trapped in Cerberus’ collars. From this sudden distraction, the warden missed the group and smashed its tentacles into the wall above the tunnel. The force from which the demons were released even pushed back the remaining demons of the stronghold, allowing the group to just make it back in the tunnel before the way collapsed behind them.

---

The group kept running and flying until they were back in the underground tunnel complex they came from and the air was black again instead of red. A few foal-sized and -shaped demons still kept chasing after them, but gave up one after another as they realized they would have no chance against them in combat anymore. Fluttershy looked back to see how many were still following them, when she realized one of the demons had a familiar body shape and was significantly bigger than the others.

“Snails?” she spoke.

The demon didn’t respond. Instead, it just gave up chasing, allowing the group to escape. After a few more minutes, they could finally stop and pant heavily in stress and exhaustion. Rainbow let Twilight down in front of the group, then flew over to the others to check on them.

“Every... pony... okay?” she asked. The others nodded.

As soon as the group regained breath, they turned to Twilight. She looked terrible. Although she wasn’t hurt, the purple mare looked like a complete mess with her ruffled mane, bloodshot eyes, tiny pupils and tear trails. She stared at her friends with wide open eyes and an expression of total fear written in her face, shaking all over and hyperventilating.

“Twilight, sugarcube. Are you alright?” Applejack worried, slowly approaching her.

The closer she came, the more Twilight retreated, hyperventilating and shaking even more.

“Twilight! What’s the matter with you? Don’t you recognize us anymore?” Rainbow wondered.

The purple mare didn’t respond and just kept on breathing heavily. Suddenly, her shaking and breathing reduced. The expression on her face became a bit more relaxed as she kept on staring at her friends as well.

“Kill the demons, kill the demons, kill the demons...” she started mumbling.

“Demons?!” Rarity exclaimed. She looked around in panic, but was unable to find any.

“There aren’t any demons here, Twilight! What’s going on with you?” Fluttershy concerned.

Again, the purple mare didn’t respond and just kept on mumbling the same words. Slowly, a grin started growing on her face, soon growing unnaturally wide while her eyes as well went wide open. Uncontrolled tears started flowing again. But these tears were not normal; They had a deep black color. Obsidian knew what this meant.

“She is possessed,” he explained.