As he read those words, the ground begin to tremble, causing him to lose balance and fall. It was  not only on this cave but all around the world. The door beneath him started to open, inside the door were blue streaks of light, as it continue to open ,the strange thing is that Kenji didn't fall instead he was floating. 

"Shit, what is happening?" Kenji complained, as he was floating. The streaks of blue light started to converge and condense around him, covering his whole body  in a blue cocoon-like shell. 

What he didn't know that that blue light is mana. As he was being covered in a cocoon. Intense pain started to invade him,  every inch of his body is feeling intense pain.

"Ahhhhhhhh!!!!" Even his mind is feeling pain like he was being tortured alive. Due to the pain his mind can't resist it and fell unconscious.

"Where am I? Ahh shit, it hurts." He woke up, with his head aching, and saw himself standing on nothing surrounded by endless darkness. Like in an endless void.

"So you woke up, it's been ages" as he was still in trance, a domineering  voice resounded.  The previously dark place startex to lighten up a bit,  a holographic figure of a female,  like a mannequin, devoid of any facial parts nor body parts, only composed by a body, arms, head and legs.

"Eh? Who are you? And where am I?" Kenji asked, startled.

"Me, You can call me, Greta. Youre in a special realm created by me, you're here because currently your body is undergoing changes due to sudden mana interaction, and if I didn't separated your consciousness from your body you might go crazy because of intense pain, but that doesn't matter," It replied, as it was missing a mouth, it voice resounded on his mind like telepathy. " What I want to say is,  Congratulations"

"For what?" Indeed, He was confused. First he woke up in this unknown place, second, There was this thing named called Greta, which appearance is out of this world and lastly is what was happening.

"Didn't you read what was written on the door? 'You have unlocked [Mana Utilization]', Is what was written right?"

"Certainly, there's something written like that." He recallled the words written on the door he saw earlier. Which made him feel more puzzled. 

"What happened is that, mana became available for use." Greta explained.

"Mana? Is that the thing that exist only in fantasy?"

"That's right."

"Then how come you are saying mana became real? Who, no what are you really?"

Stolen from its rightful place, this narrative is not meant to be on Amazon; report any sightings.

Ever since he met Greta, he was truly confused, and many questions are running on his head.

"I am one of the entities created by God, the one true God, called Frox. " Greta explained. " We Frox, are created to govern the worlds created by God, each of us governs a universe as there were countless universes out there and this universe is just one of them."

"And as there were other worlds out there, each of them has their own characteristics, some has magic, others do not. Some has technology so advance that they were capable of traveling other worlds using only mere science."

Hearing this he can't helped but be speechless, at the same time excited. Somehow he already has a faint idea regarding what is happening. 

"However some worlds without magic are capable to make magic available for use like Earth. And you are the one who unlocked it." Greta continue to explain. "Seeing your expression, it seems you already have an idea so, I will make this short for, you already spent some time here."

"Being the one to unlock [Mana Utilization] you will be given rewards. First your body went change after interacting with a huge amount of mana, if I didn't do that your body will burst and you will die, you dont want that do you?

Hearing this Kenji can't helped but shiver especially how Greta said this easily.

"Second, you will be given a special unique skill." Greta continued.

"Skill?" 

"Oh right, I forgot, your world will be like an rpg where there will be levels, stats and monsters."

"Ehh? How come?" He only thought that only magic will be available but not like those in games.

 "I don't know, I'm not the one who created and designed the worlds"

"Oh..." he frowned. " so what is the skill you gave to me?"

"I don't need to tell you, after you've gone back you can see it in your status" Greta said and continued. " and lastly, have fun and good bye. Ahh wait,  i forgot to tell you this but an hour in here is a hundred years in the real world,  and you spent 7 hours in here. With that, BYE!"

"What do you mean about that?! Hey, hey, wai-" before Kenji finished his sentence, again he lost consciousness"

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It's been a while guys, sorry if it's late, well I'm busy due to school affairs. 

Please  tell me about your comments or suggestions for me to improve.