2-B Classroom, History Department, Zenith Academy.
A young man with deep black hair was sleeping on the last bench of the classroom, but nobody paid much attention to him because he was hiding behind another student.
Suddenly, his eyebrows quivered as his eyes snapped open. He raised his head and looked around, startled and alert. Confusion filled his eyes as he surveyed the all-too-familiar classroom.
'Huh! What?'
He couldn't comprehend what was happening for a few minutes, but slowly, everything began to click. His eyes widened in shock at the realization, and he even pinched himself to check if everything was real.
'What the hell! Did I get back in time? How is that even possible?' Arthur narrowed his eyes as he thought about what had happened before he lost consciousness.
He was fighting his last battle against the Overlord of Voidborns alongside Elara, and then the beam of darkness had fallen on them, killing them instantly.
'Damn that bastard! He was just playing with all of us.'
However, he soon calmed down and heard the familiar voice of his history professor. Everything was real. He didn't know how, but he had gotten a second chance to save everything. He was now 18 years old, at the time when he had started his journey.
His eyes burned with determination as happiness surged through his body. Since he had come back in time, that meant all of his loved ones were still alive, and he still had time to prepare for the Third Cataclysm.
A grin appeared on his face as he thought, 'Just you wait! Oversized brat. I'll show you the consequences of everything you did.'
"So, Mister Arthur, is my lesson that funny to you?"
Arthur jolted awake, hearing the chilling voice of the history professor. He coughed lightly, realizing that he was overreacting. He stood up and gave the history professor a big smile.
The professor was a tall, middle-aged man with a stern look on his face. He was looking at Arthur as if he wanted to boil him alive. Seeing that fierce gaze, Arthur tensed up and tried to offer an explanation.
"Um, Professor Rey, I was just, uh, yeah, I remembered something while listening to you." Arthur rubbed his hands as a professional smile appeared on his face. He was sure this would work.
"Oh yeah, we're talking about the First Cataclysm that almost destroyed humanity. What's so funny about it?"
His classmates looked at him in mockery and curiosity. They knew Arthur too well and were sure he would surely come up with an excuse.
'Fuck! Why are you teaching that!?' Arthur was tongue-tied and ran his imagination at full potential to think of something.
Sensing the impatient gaze of professor, he blurted out, "It's something my grandfather told me. When the Voidborns attacked the first time, my grandfather caught them in the act, and he even reco-"
"Shut your nonsense and get out of my class!!"
Professor Rey roared as he slammed his hand on the table. His eyes were spitting flames, and it was clear that if Arthur didn't leave, he would have to suffer a lot.
And that was exactly what Arthur wanted. He shivered under the middle-aged professor's gaze and left the classroom at a speed that would put even a rabbit to shame.
While other students tried hard to contain their laughter, Professor Rey just shook his head in helplessness and muttered, "Your grandfather died before you were even born, brat. Who did you hear it from?"
"His ghost!"
"Hahahaha!"
They couldn't contain it anymore, and the whole class erupted into fits of laughter. Professor Rey, who was trying to calm down, looked at Arthur, who was peeking through the windows. His lips twitched as he growled, "Do you really need a beating?"
"Of course not! How can I disobey Professor Rey? I just came to take back my shoes. I forgot them here."
Arthur took the shoes and again left the classroom through the windows. Professor Rey just stood there, muttering, "One of these days, I'll kill this brat."
Arthur stopped under a tree and looked back at his classroom. Wiping the sweat from his forehead, he said, "Phew! Now we're safe."
He looked around and found no one nearby. Nodding in satisfaction, he climbed onto the tree and lay on its thick branches. He sighed as the cold breeze hit his face.
'Now then, time to see what actually happened,' his expression turned serious as he thought about the reason that could have led him to come back in time. However, even after going through everything, he couldn't think of anything that could send him back in time. It was simply impossible.
"Ahhh! I'll think about it later. For now, there are more important things to do before it gets late," Arthur groaned in frustration and shoved the topic of regression aside.
Then, he thought about what would happen in a few years when the Third Cataclysm would descend on Earth, bringing the Overlord of Voidborns along with it, who would wipe out all of humanity.
There were a total of three cataclysms that slowly destroyed Earth. The First Cataclysm happened in Year 2030 when an alien race known as the Voidborns invaded Earth.
They were terrifying and possessed immense powers. The humans tried to fight against them, but it was all for naught. The Voidborns were just too powerful, and even the nukes only managed to wipe out the weaker ones. The Void Lords, who commanded the Void Army, were immune to the nukes.
In just one year, humans lost three continents and almost 75% of their population to the Voidborns. At that point, humans, at the age of 18, began to awaken the System Core, and along with the core came the ability to become strong.
The humans then waged a war against the Voidborns with Sentinels, also known as Awakened Humans, at the top. The System Core allowed the humans to kill the Voidborns and level up, making them stronger and granting them new skills.
The humans were finally able to establish a stronghold, but then the Second Cataclysm descended, bringing the Abyssal Creatures with it. The human population once again dropped under the combined attacks of the Voidborns and the Abyssal Creatures.