The World seems Realistic but Why do I have a Leveling System?

"Ah...how could you..do this..."

The boy muttered fearfully with his complexion turning paled and his eyes reddened from crying. Looking at the bloody corpse of his friend on the ground, he remembers how it all began. 

It was just like any other days, the boy and his friends were on the way to the cafeteria while talking about nonsense that many teenagers always did. Just when the three of them had reached the hallway to the cafeteria, they noticed an unknown adult man standing quietly at the center of the path.

Looking at the man's attire and that they were in high school, the boy and his friends quickly assumed the man to be the father of someone who had come for a visit. Most of the time, one couldn't enter the school premise if they aren't a student or didn't have permission from the school itself. But there are also times that the parent of the student could visit their child even without having any permission from the school, and that is during lunch.

Nevertheless, they have to give a reasonable answer to the guard and can only stay for at most, 10 minutes. 

Without any wariness, the naive boy and his friends approach the adult man. 

"Hello...uh, Sir?"

His friend couldn't finish his greeting as the moment they stare at the adult man's face, they were surprised to see a small crimson gem that rooted deeply at the center of his forehead. At first, they thought their mind was playing a trick on them as what they had witnessed shouldn't be possible normally. And then, they thought the adult man is perhaps, a cosplayer, which would make a lot of sense. That was exactly what they concluded at the end of it.

"Do you need any help, Sir? You seemed lost."

Thought his friend was asking with good intention, the adult man stays silent and didn't give any sort of response whatsoever. The only thing that they noticed was that the adult man was looking elsewhere as if their presence didn't register in his eyes despite them standing right in front of him. Due to that, the atmosphere started to turn awkward as his friend scratch his head in embarrassment. Since the adult man didn't seem to want to talk to them, the boy and his friends decided to leave him to his device instead of troubling him.

As they turned their back on him and only took a few steps away, suddenly, one of his friends stopped on his track before coughing up a mouthful of blood as he looked down to his stomach filled with confusion. What he saw was none other than an adult hand, but what he couldn't understand is how that hand is piercing right through his chest with a blood-pumping heart in the grasp of that masculine hand. 

"Wh...at?"

That was the last thing he saw before his mind shut down for eternity, which can only mean one thing, and that is death. 

"Ryouta!"

The boy and his only friend left screamed at the sudden death of their friend in fright and fearful. Their complexion turned paled as their body trembles at the unexpected situation. They couldn't even muster any strength to run as the moment they turned their back against this mad man, they would most likely get the same end as their friend staying motionless on the ground litter with his own blood. 

"H-How could you...do this!"

The boy's friend, Roy, gnashed his teeth hard and asked despite the fear and death he felt coming from the adult man with a crimson gem in his forehead. 

"Y-You won't get away with this! The cops will surely catch you in our place!"

"W-Wait, Roy..."

The boy tried to calm his friend, unfortunately, the latter was blind by his emotions that he couldn't think straight. The only thought left in his head is to avenge for his friend's death, that is until the adult man suddenly started laughing out loud.

"What are you laughing at?!"

"Hahaha, sorry, kids, my apologies. I couldn't help but laughs upon seeing an idiot like you."

"You!"

Roy gripped his fist hard and was ready to launch himself at him when the boy grabbed one of his arms, stopping him from the suicide act. The boy clearly knew that they couldn't win against the adult man, the fact had already shown right in front of their two eyes. One must have a frightening strength and speed in order to smoothly pierce their hand through the human body, which is something an average adult couldn't possibly do. The adult man must be someone special, or so the boy thought.

The boy guessed it right. If he had let his friend, Roy, charge madly toward him, it would only be asking for death. Even hundreds of them couldn't hold a candle against the man, that was just how powerful he is. 

"Your friend is wise, lucky you. However, your luck ends the moment you met me."

Feeling his death creeping closer, the boy didn't even think for a second as he throws his old phone toward the man with all his power before grabbing Roy's hand to run away with him. 

"You think a phone can stop me? Don't mention the other brands, not even Nokia can endure against my mighty strength!"

With a single fierce yet fast punch, the boy's old phone shattered to pieces within the blink of an eye. And during that, the boy and his friend could only take eleven steps before they were overwhelmed by the smell of death. When the boy turned his head to look back, he paled as the man was already a meter away from his friend, ready to stab Roy to death with his hand. 

Without having any strength to stop the man, the boy could only watch as his friend, Roy, screams in pain when a masculine hand pierces precisely through his heart. The boy, Luke, closed his eyes as he can feel the God of Death standing next to him with a scythe around his neck, ready to take away his soul to the afterlife along with his friends. Luke had planned on playing for hours at the arcade once the school is over together with his friends, that was the plan, yet how could something like this happen? The three of them were still young and have a bright future, but to think today is their end.

If he were given a chance to avenge his friend's death, Luke would definitely take it even if he had to deal with the devil itself. Their death was just too cruel as they couldn't even resist nor question why they were killed. No, he could think of one infuriating reason for the mad man, he must be doing this for fun based on the fact that he could still laugh after killing his friend like stepping on a bug. Even if that wasn't the case, Luke would still take revenge if he were given the chance to do it.

Nevertheless, where was the pain of having something pierce through the body before the ultimate death? Luke wondered as he couldn't feel any sort of pain as he expected. Slowly, he opened his eyes. 

"Guh! W-What?"

Over there, standing next to the man coughing up blood was a person with white hair and a half-mask fox covering their face. Luke couldn't tell whether it's a he or she, but one thing he did know is that he or she is way stronger than the adult man who he thought to be terrifying. Because his eyes were closed, Luke didn't see what happened for the man to be on his knees and vomit a mouthful of blood to the ground. But based on the fact that the man is holding onto his stomach with both of his hands, Luke judged he was punched or kick right into the guts. It must be a powerful attack for sure.

"Who are you, bastard?!"

Wiping the trace of blood on his mouth, the man angrily asked. Because his mind was directed on killing the students, the man only noticed the masked guy when he/she was already right behind him. And before he knew it, the blood rushed up to his head as he coughs up a mouthful of blood. He had just noticed the presence of the masked guy, but by that time, he was already punched straight at his guts. What a frightening speed!

Without saying anything to his question, the masked guy slapped him, sending him flying straight to the wall as a response. The man didn't expect a slap to come at him when he was asking the question, and so, he couldn't protect himself from the surprise attack. 

"GRAAAAAH! You dare to slap me, this great me?!"

Along with his furious howl, Luke noticed the crimson gem on his forehead started to shine and as if his body was reinforced by something, he swears he could see the man's muscle bulge with power. 

"That's a weird gem you have there."

The masked guy spoke with a voice devoid of any emotion and a tone that one would have a hard time judging his/her real gender. With his eyes turned red like a berserker, the man charges toward her in a speed Luke couldn't follow. Within the blink of an eye, the man was already right in front of the masked guy. He sneered upon noticing the masked guy didn't do anything and stand there like an idiot, he assumed the latter couldn't follow his speed either, which would be understandable. 'Taste my mighty punch!' thought the man as he took the chance the masked guy couldn't act and fiercely punch toward his head. 

Because of the terrifying strength compressed in that single punch, the masked guy's head exploded upon contact with his fist, or so the man thought. But what really happened is that his fist was caught firmly by his enemy as if it was nothing. The masked guy didn't even move an inch from his spot, this clear demonstration of strength proven to the man that the masked guy is no way in hell lower than him, heck, he might be even stronger than him. With a solemn expression, the man asked.

"Who are you?"

As if that was what he was waiting for, the masked guy smiles and said.

"I'm Shiro, the guy who will torture you to death for killing the students without any solid reason. I hope you're prepared for it as I don't want to accidentally killed you or something."