In a corridor of blinding light, two figures stood: a young monster and a young human, the former glowing from the power that swirled inside him. His gaze was focused, his mind set. It was time for one story to end and another to begin.

"But first, there's something I have to do," the young monster, Asriel, spoke. "Right now, I can feel everyone's hearts beating as one. They're all burning with the same desire." He narrowed his eyes. "With everyone's power, with everyone's determination, it's time for monsters to go free!"

In a dramatic motion, the young monster held his hands towards the sky, preparing to channel the raw power of all the souls within him. He expected it to hit him like a bolt of lightning, but instead… nothing came.

Asriel paused, his tearful eyes widening. Frisk was no longer standing in front of him. It was as if he had simply blinked out of existence. But it wasn't just him; everything was gone, leaving him standing in a void darker than the darkest cracks of the Underground.

"W-What? What happened?" he stammered. "Frisk?"

He spun about, his eyes scanning the void. He opened his mouth as if he were about to say something…

And that's when he heard it. It was close to a rumble, like the deep groans of the Earth he was accustomed to living with, only distorted and crackled. It was if someone had taken one of the VHS tapes his father used to make and damaged them. It wasn't natural, that was for sure; there was a pattern to it, like a spoken language, though none he had ever heard.

And it was everywhere.

"✌💧 ✋ 👎 💣🕆 ."

Asriel gulped. "H-Hello?"

The voice grew louder and less distorted.

"A💧 IEL D EE💣URR!"

Asriel shivered - the voice was piercing through him like a cold wind. He straightened his back, trying to summon his courage.

"Who's there?!"

There was a pause - a second hung like a minute. That's when he noticed it: a mist rolling in from nowhere, nipping at his ankles like the touch of a ghost. Slowly, but surely, it began to coalesce in front of him, taking the form of a strange, skeletal monster. It wasn't for another moment before he noticed its strange, hole-punctured hands, its cracked skull, and its odd, ghoulish grin.

"Y-You!" Asriel gasped.

It nodded, its grin frozen on its face. Then, with a voice as smooth as silk but deep as thunder, it spoke. "So you can see me, then?"

Asriel took a wary step back. "Yes…? Who are you? What is this place?"

He tilted his head back and forth. "Not that it would mean much, but you call call me Gaster. Sound familiar?"

"I-I don't think so," Asirel said. He then narrowed his eyes, scrutinizing the creature. "B-But I-I've… I've seen you before."

"Have you now?" He mused.

Asriel curtly nodded. "Yes, all around the Underground, when I was in my…" He winced. "Other body."

Gaster chuckled, bringing up one of his hole-punctured hands to his chin in a thinking pose. "Out of the corner of your eye?"

Asriel nodded in affirmation, his eyebrows still narrowed in confusion.

"Interesting. In that case, my apologies for the…" Gaster nodded his head back in forth. "Dramatic entrance. I figured it would take quite a bit to get even your attention."

Asriel blinked. "Why did you think I wouldn't be able to-"

"Just a guess," Gaster spoke, twirling a hand in a casual manner. "Well, an educated guess, I suppose. They were sort of my thing."

Asriel squinted in confusion. "Were? I don't underst-"

"No point in wasting time on an old ghost like me," Gaster chuckled. "Let's talk about you." He leaned down, bringing himself to the shorter Asriel's level. "What is it you're trying to accomplish here?"

Asriel paused for a brief moment, than gulped, now gazing at Gaster with wary, but watery eyes. "I… I'm about make things right."

"For what?" Gaster questioned. "What did you do?"

"Y-You… you don't want to know."

"I already know what the flower did," Gaster spoke, surprising Asriel. "But that wasn't you, was it?"

"Wasn't it?" Asriel said, closing his eyes. "I remember everything… the blood, the death, the… the…" He stifled a sob, before gazing morbidly back at Gaster. "If you know, you probably hate me."

"Hate you?" Gaster tilted its head to the side. "I'm not here to judge you, child." His voice was growing noticeably softer. "I'm here to help you."

Asriel smiled tearfully. "R-Really?"

"Yes," Gaster said, raising to his full height and patting the young monster on his head. He then turned away from Asriel, gazing off into the void. "I don't have the time I used to, so let me get right to it." He took a deep 'breath'. "I've… felt things here. Things nobody would believe; the time and space of the multiverse twisting and overlapping, connecting past and present, here and there. There is magic flowing through it, flowing through every thread, through everything and everyone." He turned back to Asriel. "And it's all flowing here."

Asriel squinted in thought. "As in …"

"Our- Your home. The Underground," Gaster continued, before he began to pace back and forth. "Though I can't be certain, I do have reason to believe that it is one of the largest magical nexuses ever to exist. Perhaps it's due to the nature of monsters, or perhaps it has something to do with the humans' barrier. I don't know." He raised a finger. "But I do know one thing: it makes the Underground a ticking bomb. If the barrier were to be brought down, more magical energy will be released than in any other time in history. That is what you're planning to do, yes?"

Asriel nodded slowly. "How did you-"

"Another educated guess," Gaster stated. "And in regards to that, let me be perfectly clear: you should reconsider."

"What do you mean… reconsider?" Asriel asked warily.

If Gaster's eyes could move, they'd be narrowing. "Do not drop the barrier."

The young monster shook his head incredulously. "B-But… But why? Just because it'll release a lot of magic?! Who cares!"

Gaster moved one of his hands in a calming gesture. "Let me explain-"

Asriel ignored him, continuing: "Everyone's hopes and dreams are riding on that barrier going down! They're riding on me ! I can't let them down - not after everything that's happened. I owe it to them! Who are you to-"

"Would you rather them have nothing over little?" Gaster asked bluntly, its question piercing Asriel like an arrow, who was quickly silenced. "Not thinking through the repercussions of your actions - that's something I have a bit of experience with. I will not let you make the same mistake."

He began twitching his fingers in seemingly random patterns - out of nowhere, a cloud of red mist conjured before him.

"A magic surge that powerful will not go unnoticed."

Without warning, the cloud began to form into the shape of a strange, hunch-backed humanoid with jagged, elongated claws for fingers. Asriel gazed at it, unsettled, and the entity gazed back at him.

"There are things out there, terrible things, that will sense it …"

The cloud of mist twisted into another figure, a strange, one-eyed triangle. While Asriel saw it had no mouth, he could practically feel the creature grinning at him.

"- things that human and monster alike should be grateful are currently dormant."

As he spoke, the mist continued to take various forms: a tall, faceless humanoid, a shape-shifting mass of jagged limbs, and finally... a strangely familiar face, though ones with eyes that could pierce a shadow.

Gaster took a deep breath, the mist vanishing. "And that's just the start of the mess it could create. Space-time is already unstable thanks to... " He gazed away from Asriel. "Recent events. I have good reason to believe that this will work as a catalyst to a resonance cascade - the breakdown of dimensional membranes." He held two of his hands apart. "Realities that are separate …" He clasped them together. "Will become one."

Asriel shook his head in confusion. "That… I don't understand what you're saying."

"I don't have time to explain the multiverse theory and all its various facets," Gaster grumbled. "You're just going to have to trust me."

The young monster gave Gaster an incredulous look. "Even if I did trust you, you just said that you're not even sure this will happen! You're putting the future of humans and monsters on an 'educated guess'!"

"This is bigger than humans and monsters, young one," Gaster exclaimed. "And I am 99% certain I am correct."

"Even then, I still don't get exactly what sort of bad things will happen," Asriel exclaimed.

"Weren't you paying attention?" Gaster mumbled, rubbing his skull for a head in annoyance. "You are just like another of my former students - no attention span, always with his head in the clouds. But that doesn't matter - let me say it again: there are powerful forces both in the outside world and beyond, and they have nothing but ill will towards all that lives. If you drop the barrier, they will come for you - all of you - and that could be the least of your problems."

"Then I say let them come," Asriel's said, his eyes narrowing in determination. "Don't you know what's been going on? Frisk and his friends have proven that if monsters and humans work together, there's nothing they can't beat!"

Gaster sighed. "There is no deterring you, it seems. You are as stubborn as my former student as well." He chuckled. "I told him you would need proof - that you wouldn't listen without it, and I was correct." He held up a hand. "But unfortunately, my social time is nearly at an end. However, before I go, on the very likely event you go through with this, I will echo my… partner's words." He took a deep breath. "Prepare for unforeseen consequences."

With a flash of light, the mysterious monster vanished, and Asriel blinked back into the real world, ready to complete his work. As the power of the souls within him pulsed like a beacon, the words of Gaster all but disappeared from the back of his mind.