White-haired men

 [Very well!]

Suddenly, the black smog turned and spiraled into the air, the horrific sound intensifying even more. Once it reached a particular height, it began swirling downwards with an even greater speed and sinister sound. Its spiraling action seemed to cause the air to move violently, creating a violent wind that surrounded Tyler, violently raising him into the air towards it.

The pages were still flipping rapidly, releasing the last bit of black smog between them.

Tyler could only watch as his body was lifted into the air to meet the swirling tendrils of black smog.

The black smog swirled into his mouth forcefully prying it open, and some of it flowed into his nose. His head fell back, his hands and legs spread out, and his back arched backward, his eyes bulged out like he was being suffocated.

The wind that was surrounding him spiraled up his arms and legs, wringing his skin and shredding his clothes.

Its turning effect on his body became so severe that it began twisting his bones into awkward positions as bone-crushing sounds filled the air.

His legs, arms, and neck were bent in awkward, painful positions. And the worst part was that he could not scream from the excruciating pain as his mouth was filled with black smog.

The smog's last tendrils entered his body, and warmth emanated from deep within, spreading throughout his being. The initial sensation was pleasurable, but it quickly transformed into an intense, burning heat that coursed through his entire body.

He could no longer contain his anguish, and a deafening scream erupted as a golden glow intensified from his body, enveloping the surroundings and causing an explosion! 

zzzzzzzzzzzzzzBOOM!

He looked like a human-shaped sun in the air.

The golden glow expanded outward before retracting into his body, following the contours of his form into his chest. His bones returned to their rightful positions, and he crumpled to the ground.

He lay there panting, his body aching, and his clothes in tatters.

Tyler looked up at the book, which was now closed, floating there silently. He didn't know what had happened, but he knew that his life had taken a dark turn! Because, during that whole ordeal of pain, the wailing sinister voices constantly whispered sinister thoughts in his head.

"Kill!"

"Revenge!"

"Make them suffer!"

What was even scarier was the fact that all these voices sounded like him, and he was drawn to listen to them!

-So this is what it means to be a demon.

His body felt different. He felt a lot of pent-up dark energy in his body- energy that probed evil thoughts in his head.

Clenching his fists, he discovered his exposed forearms were a little muscular compared to before. Amidst his awe, he recognized that the stinging pain he had from the beatings all over his body and face had disappeared. With his fingers, he traced the left side of his face and discovered that it was smooth and flawless. The scar that ruined his good looks for most of his teenage life was gone!

-wait!

Immediately, he stood up, pulled his tattered sleeve up, and checked his left shoulder for his spiritual emblem. The mark served as a constant reminder of his disability and bad decision-making.

There it was - no longer was it a black smudge tattoo. It had turned golden and developed the shape of a flame. His emblem had activated! He wasn't spiritually crippled anymore. He could now wield mana! On closer inspection, his flame emblem appeared kind of different from other flame emblems - it had a pair of unidentical wings in its heart.

-This? I did not expect this! It awakened my disabled spirit!

-I can finally attend the Elite Academy.

[No, actually, you cannot wield mana. Your powers run on dark energy which you must obtain from feeding on negative emotions you cause on living beings]

"So, I am a demon now?"

[Not yet. You're only a half-demon. If you were, your sinister conscience would have already controlled you by now. You could call it your demon. But don't worry, for now, you still retain part of your righteous conscience.]

"Ahh.....so that's what you meant by the downsides,"

Tyler guessed the whispering voices in his head were his sinister conscience. This meant his conscience was now warped- things were going to be difficult if his conscience sided with what was wrong. He wouldn't feel guilty if he killed or committed a crime.

[Yes...You have to increase your mentality to A rank before you fully turn into a demon. You have approximately 4 months, otherwise, you will lose control and will kill anyone. Even those close to you. That is the least of your worries - you might attract unnecessary attention before you get strong enough to defend yourself. The consequence would be death]

A period of silence reigned as Tyler comprehended everything the voice had said.

"What about the inventions? How do I make them?"

[At the moment, Your current IQ enables you to comprehend a maximum of 45 concepts. These 45 concepts will allow you to build 1 kind of technology. You will have to increase your IQ to gain more concepts and invention manuals. The next concepts you will have to learn require a minimum IQ of 600. To increase your intelligence faster, I suggest playing brain-challenging games like chess, complex puzzles or reading new complicated text information daily. Do not expect results immediately.]

"Hmm....as simple as that?!"

[It isn't supposed to be. Surprisingly your IQ is quite high for a 16-year-old. Therefore you will have it easier to increase your IQ.]

The book gently flew over to where Tyler was and flipped to a page that had a glowing golden title [Wielder attributes]

[Infernal Architect: Tyler Castiel]

[Rank: G-]

[Strength: G-]

[Agility: G-]

[Endurance: G-]

[Defense: G-]

[Mentality: G]

[IQ: 500]

[Charm: G-]

[Skills: Flame Dagger level 1]«Reach level 5 to unlock a new skill»

[Dark energy: 20/50]

-Of course, my IQ is high because I am a 20-year-old engineer in a 16-year-old body.

-Wait a minute? Castiel's not my second name.

"Hey, book..."

Even before Tyler could finish his sentence, the voice interrupted.

[My name is Ramiel. I am a different entity from the book]

Tyler's pupils constricted to the size of needles as shock gripped his heart.

"@#%^!!#"

"So you are that fallen celestial who wrote this book!!!!!"

*

An hour after Tyler had left, two people stood at the spot where the book was previously buried, staring at the empty hole that was now left. They were two men with tall lean figures and white hair. They wore identical black overcoats and sunglasses. "I'm sure I left it here! Someone must have taken it!" one of them said panicking.

The other one sighed helplessly and pinched his brows in disappointment, "Picked it?! Of course, someone picked it!!!! Now look at the huge mess you've caused. A school? You chose to bury that thing in a school? Seriously?!"

After letting out a chuckle, the man suddenly slapped the other man's head and yelled, "Quick! GO AND TRACE IT DOWN YOU IMBECILE!!!!!!!! IF WE DON'T FIND IT WE ARE GOING TO DIE FOR SURE!!!!!!!!!"