The old man fulfilled his words and indeed came back three days later. During those three days Kai had not done anything other than try to perceive the elements. Just by using darkness and ice, he has gained a really high advantage against others so what if he could control them all? The temptation of being able to use them all had baited Kai to do his best.

"Kid, how's your progress?"

The old man stood beside Kai who was meditating.

Kai opened his eyes and looked at the old man.

"I don't think it's too bad."

Kai held out his palm and it was obvious that the darkness was even darker now. It had a mysterious feeling to it when compared to his old attacks that were simply like shadows save for [Black Hole].

"Hooh, it's plain to see that your connection with the darkness attribute is even stronger now, good. This is your goal."

The old man held out his palm and a small ball of darkness materialized on it. It was so dark that when Kai looked into it, he found himself slowly reaching out for it.

"Oi."

The old man slapped Kai's head.

"You would've given up your hand if you had touched that."

"Hahaha..."

Kai gave a dry laugh and rubbed his hair.

The old man straightened his back after stretching and gestured for Kai to follow. Kira followed close behind them.

They had gone to the river they had previously met at.

"You had the correct idea, you should focus on water first. Darkness isn't near any of the other primary elements and so you should focus on ice. You had the options of water and wind and you chose water hence we will start with this."

The old man raised a small pillar of earth from the middle of the river and sat above it. He crossed his legs and gave a smirk at Kai.

"Go over here."

The old man made stone steps with a distance of three steps each, Kai used them and got to the center of the river.

"Now..."

The old man bit his thumb and wrote a magic circle on the floor. The old man murmured something and the circle glowed, it etched into his hand.

The old man then aimed his palm towards Kai and the magic circle on the old man's palm glowed even brighter.

"Seal."

Kai felt that his powers were blocked by some force once the light had hit him, it was like when Reo had sealed his ice for the first time.

"We're going to start the first part of training to understand water."

The old man raised his index and middle finger and several walls of earth surrounded the river. He then snapped his fingers and the water level rose rapidly, the stone steps went back to their original places under the river.

"Oi!"

Kai was swimming above the rising water as the old man placed a roof above them.

"Now, you will learn how to use your five senses underwater."

The water filled up all the way to the ceiling and the ground below the river sank. It was quite the insane remodeling, it was impossible to be done by anyone below a B-class. Kai was awed by this fact but only for a moment, he had been submerged in water; his power of ice has been frozen and he'd drown in five minutes.

Kai tried punching the walls but his physical strength wasn't enough for him to break it under the pressure of the water.

Kai even tried going to the old man but he couldn't find his way under the darkness of the water.

"Remember, use your senses."

It was at least threre minutes in the water and Kai was almost at his limit.

Think. Think! What skill can I use to find things underwater?! The old man has an air bubble around him, I can at least breathe if I get my head in.

Echolocation!

Kai closed his eyes and focused on his hearing, he snapped his fingers but he couldn't hear anything under the water. He could try yelling but that would immediately make him lose his breath and it isn't a sure chance that he'd actually be able to use echolocation. He had heightened his ears with magic but that was different.

With that, five minutes were up.

Kai was forced to release his breath and he struggled for air- not.

Kai was amazed to see that he could breathe normally, the water wasn't going inside his mouth or nose.

"HAHAHAHA! You held onto your breath for five minutes for no reason at all! I told you to focus on your senses not to get out of this place!"

Kai could imagine the old man rolling around the floor and laughing like there's no tomorrow.

"Shut up, old man!"

"F-fine-hahahaha! Alright, alright! I'll tell you your goals."

The old man coughed and began explaining.

"This test has a maximum time of three days, this place is constantly expanding and the walls are constantly thickening, the longer you take; the higher chance you'd die. A very small part of the wall here has a weak spot, with the right amount of force and the proper strike, the wall will break no matter how thick. But, you need your sense of hearing and sense of touch mastered to actually be able to find it and your sense of sight to strike it accurately."

Kai cursed inside his mind. How would I be able to do that?! Nobody on Earth has gotten close to being able to do that without any help! Right now, I'm a normal person since you've sealed my magic.

Of course, Kai didn't actually dare to complain lest the old man stop teaching him how to manipulate elements. Besides, he had to increase his mastery with his five senses sooner or later.

"Alright."

Kai simply nodded and closed his eyes. Kira was beside the old man and was watching Kai from inside the air bubble. He was quite mad with the old man but understood the situation seeing as how the barrier could see everything in the outside clearly.

"Your friend is quite smart, isn't he? A kid would never think of methods like he's trying now- no, even an adult wouldn't be able to think of anything like that."

The old man kept on talking with Kira one-sidedly and Kai kept trying different methods as the three days passed. Kai had learned how to use echolocation and could identify the structure of an object just by simply touching the surface, Kai used his astral body to achieve his sense of touch. His sense of sight also provided him clear vision of up to five meters under dark water.

Right now, the walls were closing in so much that only the area where the old man and Kira sat at was free to move in. Kai could simply step on the wall and stretch himself and he'd reach the other side, he needed to break it fast.

He has continuously been punching one side of the wall as there were countless cracks that Kai had yet to identify.

The walls continued closing in until the old man and Kira were the only ones safe and Kai was already unable to move, the most he could move was stretching his arm and head. His legs were already immobile from the distance that the walls had already captured.

"This is my last chance!"

Kai leaned back his head.

"HAAAAAAAH!"

BANG

Kai landed a head butt on the wall in front of him.

"...I failed."

So this is how it ends? I couldn't even complete a lesson given by an old man, so much for unlimited potential.

Crack

Eh?

Kai looked forward and saw the crack he had head butted spread.

"...Did I find it?"

Crack crack

"I DID, HAHAHHAHA!"

Kai leaned in once more and head butted it once more.

The whole wall began cracking and fell apart, water began to spray out of tiny holes until it finally burst dragging Kai along with it.

Once the wall broke, the spell on Kai had already worn off and swallowed some-no, a lot of water. Kai spun multiple times and had to vomit out the water in his system.

Kai looked down on the floor and stood up after a few seconds. He raised his hands and roared.

"I did it! I completed your test, old man!"

The old man appeared in front of him along with Kira then the old man laughed.

"Hahaha, so you did, kid. I'll give you an hour of rest and we'll immediately begin the next phase."

Eh?

"I think you mean a day..."

"No, an hour."

Kai instantly did all he could to rest after his words, he drank several things from his pendant like a healing potion which he had found inside and some herbal medicine he had made.

The old man looked at him as the smile on his face vanished.

People from another world sure are frightening.

The old man quickly put on his normal expression again and nobody noticed, not the tiger nor Kai.