Transformed into Cosmic Horror in a Sci-Fi Universe

…What happened while I was away?

[Aaah! Run away!]

[Park Yujin… It’s the Abyssal Demon, Park Yujin!]

[Crash! Boom!]

Why was Park Yujin killing people and destroying the world, being called the Abyssal Demon?

While I was observing other universes, what transpired here? A quick glance at the logs revealed that the fragile human mind couldn’t withstand my power and was ultimately consumed. As a result, his rationality vanished, leaving behind only a destructive instinct, turning him into a lower-tier Outer God-like entity.

The more severe issue was that no one possessed the strength to stop this rampaging being consumed by the power of an Outer God. That made sense. In a universe where so-called gods were merely powerful interdimensional beings, I had bestowed genuine Outer God power. Now it was running amok, and there was nothing they could do.

People were being crushed by overwhelming power, and just meeting his pitch-black eyes caused them to lose their will to fight or go insane with fear.

Wow, this is a real disaster.

Initially, he was a regular being in this universe, not particularly strong, but he suddenly grew and became a world-destroyer. This meant that the universe’s will couldn’t even create a counterbalance. In other words, this universe was doomed.

Interdimensional monsters were out of the question, and the so-called gods in the divine realm couldn’t interfere. On Earth, there was no one who could stop the rampaging Park Yujin.

The conclusion was the destruction of the world.

Oh no… What was I thinking when I directly gave him power?

I should have created an avatar similar to myself, like the Elf God Rios did, and made it a constellation. This was a mistake driven by my curiosity and excitement, without deep consideration. Of course, I could simply reverse the world’s time or erase Park Yujin’s existence to resolve everything.

The reason why gods are said to never make mistakes is that even if they do, they can perfectly cover it up as if it never happened. Just as I was about to turn back the universe’s time to before Park Yujin’s awakening—

[Wait a minute.]

An incredible idea suddenly struck me.

[A constellation story, world destruction, final boss… Isn’t this the perfect setup for a regression story?]

A demon that destroys the world. A regressor who knows the future struggles to prevent it… Absolutely possible!

Alright, let’s choose someone to be the regressor. This time, I’ll create an avatar in the divine realm to prevent them from being consumed by power. The avatar will use up all its power and disappear, sending the regressor’s memories back to the past.

Oh, there’s a character in the perfect situation for this. I’ll make him the regressor.

#

“Huff, huff…”

C-rank hunter Lee Junhyun. With his detection skill, he barely managed to survive Park Yujin’s attacks. But now, it was the end.

Six months had passed since Park Yujin went berserk and became the Abyssal Demon. He had swept across the world at an incredible speed and returned to his homeland, Korea, to finish everything off.

This was the end. Korea, which had a few surviving hunters during the early stages of his rampage, was now doomed with his return. Even the world’s strongest hunters had gathered to face him, but none could withstand his terrifying power and fear.

‘Is this really the end?’

Lee Junhyun had managed to survive by evading with his exceptional detection abilities, but now he had reached his limit. All the hunters were dead, and countless civilians had been massacred. There were no hunters left. He might be the last one.

If that were the case, the monster that had slaughtered all the hunters would come for him next. He was certain of it.

“…Damn, he’s here.”

His detection skill sensed an overwhelmingly ominous presence. In this world, there was only one being capable of emitting such an aura, both in the past and the future.

“The Abyssal Demon.”

The Abyssal Demon, Park Yujin, had approached Lee Junhyun, staring down at him with those characteristic pitch-black eyes.

“Huff, huff, huff!”

The moment their eyes met, an indescribable fear began to consume Lee Junhyun’s mind. It felt as though an invisible force was crawling all over his body, binding him tightly and rendering him immobile.

His entire body froze. He couldn’t make a sound. He couldn’t even swallow. It felt like making the slightest noise would result in his immediate death. Even if that weren’t the case, he was as good as dead already.

Swoosh—

Just as Park Yujin reached out to kill him—

[My avatar.]

“…Huh?”

Suddenly, a voice echoed in Lee Junhyun’s mind, and he felt the fear and headache dissipate. It was as if someone was protecting him, giving him a warm and soothing sensation.

‘What is this…?’

Just as he was bewildered by the sudden change, something even more startling happened.

“Kieeeek!”

Park Yujin suddenly opened his mouth wide and let out an enormous scream.

“H-Huh?!”

Startled, Lee Junhyun recoiled, watching as Park Yujin continued his bizarre behavior.

“Keeek! The Great One! The Great One is coming! Welcome Him! Welcome Him! Welcome Him!”

For the first time since his rampage as the Abyssal Demon, Park Yujin’s mouth opened, and the first words that came out were, “The Great One is coming. Welcome Him.”

Immediately after, Lee Junhyun felt his consciousness slipping away, as if being gently put to sleep by someone.

“The Great One!”

In his fading consciousness, he could still hear Park Yujin’s eerie screams.

#

Lee Junhyun slowly opened his eyes.

“Ugh… Huh?! Where am I?”

As soon as he regained his senses, he frantically looked around. But the Abyssal Demon Park Yujin, who had been in front of him moments ago, was nowhere to be seen. The ruined cityscape destroyed by Park Yujin was also gone.

All he could see was an endless white landscape. No, there was one thing.

In the midst of the white expanse, something else stood out.

It was…

“My avatar.”

“You are…”

A Western old man with a bushy beard and a friendly appearance stood before him. Instinctively, Lee Junhyun knew that this was his constellation, ‘The Legendary Prophet Who Even Sensed the Future.’ Despite the grandiose title, it was a bit disappointing that he had only granted Lee Junhyun a moderate detection ability. Still, this being had made him a C-rank hunter and enabled him to survive until the very end against the Abyssal Demon.

“How…?”

How was he able to meet his constellation directly? Where was this place? What was happening now? He had countless questions.

But the constellation shook his head as if there was no time and said, “You have perished. Just as I prophesied.”

In a calm tone, he declared that the world had been destroyed by the Abyssal Demon, as if confirming his words.

“…You could have told me if you knew in advance.”

“Excessive interference is forbidden. I’m sorry. But that’s not the issue. Listen to my explanation.”

The constellation began to explain to Lee Junhyun, who still couldn’t fully grasp the situation. He revealed that he had foreseen the future of destruction and had prepared to change it by turning back time and sending someone back to alter this fate. He had sacrificed his own existence to make this possible. And Lee Junhyun was the chosen one.

He also mentioned that he would infuse as much of his power as possible into Lee Junhyun during the regression.

The sudden rush of information left Lee Junhyun greatly bewildered.

“Wait, so you’re saying… I have to go back to the past and stop that monster?”

“Yes. But there are limits. I can’t turn back time to before he awakened his powers. Even my strength has its limits.”

He must track him down and stop him after he has already gained his powers. It will not be easy. The Abyssal Demon was an exceptionally talented individual even when he was just a regular hunter.

“But if you accept all of my power… it might be possible.”

“Wait, hold on. I don’t understand any of this…”

“I’m sorry, there’s no time. You must go now.”

Lee Junhyun was still confused, but the constellation, with a sense of urgency, extended his hand towards him.

“Wait, just a moment…!”

Lee Junhyun waved his hands frantically, but his body had already begun to fade away. Moments later—

“…Huh.”

Lee Junhyun found himself waking up in his old officetel room from the past.

“……”

It wasn’t a dream. Everything that had happened—the rampage of the Abyssal Demon, his death, and meeting his constellation—was real. It was too vivid to be a dream.

This meant he had truly returned to the past to prevent the Abyssal Demon’s rampage.

“Damn it. Sending me back without any explanation…”

Of course, he didn’t have a clear plan. He felt nothing but resentment towards the constellation who had sent him back without any further instructions.

“Hey, this isn’t fair. This is too much.”

There was no response. Of course, there wouldn’t be. The constellation had said he was sacrificing his existence to make this happen. This meant that the constellation’s existence had completely vanished—past, present, and future.

“…Sigh. Fine, let’s see what kind of power I’ve been given.”

Lee Junhyun decided that there was no point in blaming anyone for what had already happened. The constellation had done this to save him and Earth, so he decided to understand and move on. The spilled milk couldn’t be gathered back; what mattered now was understanding his abilities and devising a plan to stop the Abyssal Demon.

“Status window.”

In this timeline, Lee Junhyun had only recently gained his abilities, but he was well-versed in calling up the status window from his previous life. The familiar semi-transparent window appeared before his eyes.