The next few weeks were filled with constant visits from Equestria. After a talk from Undyne and Fluttershy, the monsters understood the logistics of moving an entire nation to another world and the associated difficulties, but both the monsters and the ponies who knew of the Underground had no doubt: this budding friendship was going to lead to something big. The anticipation was tangible, the monsters filled with true hope for the first time in years. Luna found herself going for reasons not political, and Asgore found himself looking forward to seeing Luna specifically. Neither really understood their feelings– Luna had spent a thousand years devoid of knowing how to love and Asgore had forgotten what it was like to be loved. So the two walked parallel paths, unsure how to cross to the other side.
Thunder rolled in Tartarus. Cozy Glow sighed in annoyance.
"Does it EVER do anything other than storm here?" she asked in exasperation, pacing her cage.
"Oh, well, not since you got here," Tirek muttered. "Must be your kind punishing you," he mocked.
"Aaaaauugggghhh!" Cozy yelled. "STUPID TREE OF HARMONY! I’D HAVE WON IF NOT FOR--" she cut off as her body turned black and scattered in the wind.
"What the-" was all Tirek could say before he shared a similar fate.
Far away, a being cast a powerful work of magic, and the King of Shadows was reborn. And the Master of Evil smiled, a cruel, dark smile, and Harmony shivered. The Master of Evil called, to those full of hate and of fear. To the Queen of Changelings, and the Siren Sisters.
To the Soulless Prince of the Delta Rune.
The first step was done.
Flowey cringed and cried in pain as he was dragged away from his spot in Snowdin. His eyes blinked open. He was in a small patch of dirt surrounded by stone. A table sat in front of him. He tasted magic in the air and bright light gleamed from above. Sunlight.
"What the... hell are you?" he asked in disgust as he noticed the creature who had just appeared.
"I am a CHANGELING, insolent--!" she spat before noticing Flowey. "I’m sorry, are you a flower?"
"Yeah? What of it?" Flowey mocked.
"THAT... Uh... Tirek? Where am-" a new voice was cut off by a grunt. "Oh, there you are."
"Damn it. I was hoping I’d get away from you," Tirek, presumably, moaned. "Queen Chrysalis? Are you responsible for bringing us?"
"I wish I had that kind of power," Chrysalis muttered. "I thought you were in Tartarus?"
"Wow, Tartarus? Well... that’s certainly a lesser punishment than we were cursed with," a now fourth voice scoffed. "Aria? Sonata? You’re not injured, are you?" the golden-skinned human asked.
"Nope!" a blue-skinned human declared proudly, standing up.
"I’m fine," a purple-skinned human mumbled.
"Great, so I’m naturally the only one who had to SUFFER getting here!" Flowey yelled in exasperation.
"You’re a flower," the pegasus commented.
"YES, and I was dragged by my FREAKING ROOTS! Whoever got me here better have a REAL GOOD explanation," Flowey muttered.
"Well, I don’t have that explanation," a haughty voice boomed.
"Oh, I bet you’re a real funny guy," Flowey snarked.
"You’ve got a lot of nerve, you know, talking back to the King of Shadows," the voice huffed as an ash-gray unicorn with a crimson horn appeared.
"And you know you can’t hurt me," Flowey smirked. "Obviously we were all brought here for a reason, by someone really powerful, and I doubt they’d want to have any of that effort wasted."
"And your observation is correct, Prince Dreemurr," an eighth voice said as a blue ram strode into the room.
"I’d be surprised that you knew my last name and former title but... well, can’t really feel emotions other than a permanent sarcasm and joy in depravity," Flowey quipped.
"I am aware," the ram nodded. "Welcome, all. I am Grogar... and I require your aid."
"Master," the golden-skinned human gasped, kneeling. The other two followed suit.
"Rise, my beautiful Sirens. My apologies for not aiding you against... Princess Twilight," Grogar sighed, placing a great hoof on the stone table.
"I know who she is, she’s the purple horse who visits the Underground," Flowey commented dryly.
"And also their greatest enemy," Grogar said, motioning toward everyone else who’d gathered.
"What does the King of Monsters need our help for?" Tirek asked.
"Hold up--" Flowey interjected.
"He means King of Equestrian Monsters," Grogar explained. "I need all of you to help me take down Twilight Sparkle and her friends. They are only strong because they work together, and we must do the same if we are to defeat them!"
"How will that work?" Chrysalis asked snidely. "Ever since my children betrayed me, I’m hardly keen on working with others."
"I second her opinion," the unicorn scoffed. "I work alone or above. Not beside. And I bow to none."
"How did that work out for you last time, Sombra?" Tirek quipped. "I heard you were destroyed by the Crystal Heart."
Sombra glared. "I know what to expect now! I cannot be surprised!"
"You will work with me!" Grogar demanded, slamming his hoof. The pegasus and Tirek nodded quickly. The "Sirens" bowed their heads in reverence and finally Chrysalis and Sombra gave in. Only Flowey held out.
"I dunno. What’s in it for me?" he asked. "I mean I get that they’ve got revenge but I don’t have a quarrel with Twilight and her friends. They actually finally did something interesting, which is a worthy accomplishment in my book."
"What if I were to... reward your cooperation? Perhaps with a soul and a real body?"
"...I'm interested. How powerful of a soul?" Flowey asked.
"Equal to a human soul. Do we have an agreement?" Grogar asked with a smirk.
"I believe we do," Flowey cackled. "Do I get one first and the other when we're done or both right now or both when we're done?"
Grogar confirmed, "You will get both when Twilight Sparkle and her friends are defeated. But as a token of goodwill...” he tapped his necklace and it glowed, sending light toward Flowey, Tirek, and the Sirens. Tirek grew in size, his brown areas turning red, the Sirens received ruby necklaces, and while Flowey didn’t get any new physical features, he felt stronger, and he figured out that Grogar had boosted their magic in some way. "First,” Grogar said after they all had a chance to adjust, “introductions, since you all have new faces." He pointed at each member as he spoke. “Sombra, King of Shadows. Chrysalis, exiled queen of the Changelings. Lord Tirek. Cozy Glow. Sonata Dusk, Aria Blaze, and Adagio Dazzle. Flowey, reborn husk of Asriel Dreemurr, Prince of the Underground.”
“Lord, might I ask something?” Aria asked when Grogar finished speaking.
“Of course, Aria.”
“Why is Cozy Glow here beyond having history with Twilight Sparkle? She’s only a pegasus, and a kid at that.”
“Excellent question. The ponies would say that ‘one good turn deserves another.’ Her plan to drain Equestria of magic is what freed me from my prison in the stars, so I felt it was only fair to free her from Tartarus. Now, any more questions?”
“What’s your plan, Grogar?” Chrysalis demanded. “I honestly can’t see how you’d need all of us, especially the flower. Didn’t he say he’d never had quarrel with Twilight Sparkle?”
“Hey, don’t judge me. I’m bored with the monsters in the Underground. I mean, there’s only so many times you can rewind time before you learn everything,” he chuckled slightly and maliciously.
Everyone except Grogar reacted with pure terror. Chrysalis and Sombra flared their horns in instinct and Tirek summoned a ball of fire. Flowey simply ducked into the dirt and popped up on the top of the stone overhang above.
“Missed me,” he said with a wink.
“Stand down, you three,” Grogar muttered. “Try not to kill each other, I have a few things to do.”
Twilight cringed briefly and staggered in front of Undyne and the skeletons shortly after greeting them on a visit.
“Ya alright, Twi?” Applejack asked before her front legs buckled. “Ah... Ah feel it now.”
Fluttershy shuddered and collapsed. Undyne ran to her side while Pinkie experienced similar effects. Rarity and Rainbow followed soon after.
Whatever had happened passed quickly and Twilight ran a quick diagnostic spell to confirm nobody was harmed or changed in any way.
“What was that?” Pinkie asked. “That definitely wasn’t Pinkie Sense... It felt like... something really bad is about to happen,” she whimpered, pinning her ears back.
“We need to get to Equestria,” Twilight decided. “Sorry we had to leave so soon, but...”
“It’s alright, guys,” Undyne grinned. “If you find any, go beat up some bad guys for us.”
Twilight replied with a nod before teleporting herself and the ponies to the golden hall where the portal lay. Luna galloped in immediately after.
“You felt it too?” Fluttershy asked.
“Indeed, We– I did. I would be surprised if Tia did not as well,” Luna confirmed. They opened the portal and galloped through, Twilight immediately teleporting everyone sans Luna to the Tree of Harmony. An unexpected sight awaited them.
An alicorn faced them, standing at the base of the tree. Her coat was Celestia’s brilliant white and her eyes Luna’s deep cyan. Her mane held six colors, one for each Element- orange for Honesty, pink for Kindness, light blue for Laughter, purple for Generosity, red for Loyalty, and magenta for Magic. Her cutie mark was the Elements arranged around a symbol of the moon within the sun and she glowed with golden light. The ponies instinctively bowed and a soft laugh came from the alicorn.
“Do not bow, heroines. I am no royalty or deity. No, among you, I am merely Harmony. A manifestation of these Elements you bear, and of the spirit of this land.” she said, her voice resonating. Even Pinkie remained silent, in awe of her majesty and grace. “It is good to know that you heard my cry. Equestria... nay, perhaps the whole universe, is in very grave danger. An evil old as time has resurfaced. Twilight Sparkle, you may know his name. The rest of you may not. He is called Grogar. The Master of Evil, and the creator of the darkness that plagues Equestria.”
Twilight shivered. “Wasn’t he defeated by Gusty the Great thousands of years ago?”
“In a sense, yes,” Harmony nodded. “But her methods were less than permanent, it seems. Gusty banished Grogar to the stars– you have seen the constellation known as the Ram, correct?”
The ponies nodded in affirmation.
“That constellation was his prison. It has been so for many ages, but... a recent event caused the magic binding him to weaken, and he escaped,” Harmony explained.
“Cozy Glow,” Rainbow muttered.
Harmony nodded. “Just minutes ago, he opened rifts into Tartarus, into the human world, to the world you just exited, one elsewhere in Equestria, and one beyond the grave.”
“Tartarus?” Rarity gasped.
“The human world?” Twilight asked.
“The world of the monsters?” Fluttershy squeaked with knit eyebrows.
“B-beyond the grave?” Pinkie stammered.
“Where in tarnation in Equestria?” Applejack wondered.
“Even I do not know. His magic... It blocks even my own, and I do not know why he would have opened the rifts. It is disturbing,” Harmony admitted.
A fluttering of wings took their attention. Celestia and Luna landed at the entrance of the cave and beheld the scene before them.
“Celestia Iliosa, Luna Fengaria, welcome,” Harmony greeted them. “I am Harmony, manifestation of the Elements. You heard my cry because you once wielded them, though my apologies for causing you any pain.”
“It is an honor to meet you,” Celestia said with a slight dip of her head.
“Indeed,” Luna added, mesmerized by Harmony’s existence.
“Now that you are here, we must prepare for Grogar’s inevitable return,” Harmony declared, turning to the tree. “His position in the stars, unfortunately, allowed him to observe all that has gone on in the millenia since his imprisonment, including Luna’s... transformation and all of Twilight’s adventures. He knows how to counter every move you might repeat from past quests, and he’s learned who you are, and he knows your fears and weaknesses.”
“Then... how are we supposed to defeat him?” Rainbow asked. “Ooh, what about those rainbow forms we used to defeat Tirek? Even we don’t know everything they can do!”
“Not a terrible concept, but... I’ve got a different idea,” Harmony said with a mysterious smile. She walked over to the Tree and touched her horn to its trunk. The Elements of Harmony exited and returned to their bearers. Twilight grinned at the familiar weight of the crown on her head. Sudden beams of light struck the other princesses, and Celestia gained a silver crown with a sun-shaped topaz. Luna was gifted a steel blue tiara with a moon-shaped opal. The two took a moment to admire their new regalia.
And then the Tree shattered.