Akumāo took some time to ponder on what to do next. 

"So, the more progress I make, the harder it will be to win"

 This information was undoubtedly intriguing as it meant finally having a challenge, yet not enough to make him hesitate in continuing his journey. 

He moved through the valley, battling creatures that appeared effortlessly, laughing and destroying as he went. 

Akumāo reached what seemed to be a village after many kilometers of uninteresting terrain.

"Maybe I'll find a clue here"

he thought.

 Entering the village, he was surprised to be welcomed by the locals.

 "Welcome to Luminia Village" they greeted. 

Akumāo, not wanting to appear arrogant, returned the courtesy with a smile.

 Before he could proceed, a woman stopped him, placing a hand on his back.

"Wait" she said. 

Curious, Akumāo turned to hear what she had to say. 

"I know you're probably busy, but this village needs help"

"Help?" Akumāo asked, the woman looked more concerned and nodded, After some thought, given the circumstances, there was no reason to rush in his journey, so he agreed to hear her request.

"This way" she indicated, leading him to her house.

 Inside, she offered Akumāo a cup of tea, which he accepted. "We need help against a very strong enemy, it's said that even a drop of his power could wipe out entire nations"

"Entire nations, you say?" Akumāo echoed.

"Unfortunately, that's the truth, he's the boss of this dungeon, resembling a clown, his specialty lies in having a deck of cards, each with a different magical effect, His name is Mr. Deck"

Akumāo paused for a moment before lightly smiling and responding

 "Understood, I'll take care of the situation"

At this, the woman became suddenly excited, clearly pleased that her request had been well received

 "Thank you so much"

"To reach Mr. Deck, you must head to the road of the floating mountains, his place is at the highest point, appearing initially as a circus but is, actually, an enigmatic interior"

Listening to the directions, Akumāo exited the woman's house, searching outside the village for this road of the floating mountains. With his extraordinary powers, he expected no difficulty in facing such an opponent. However, the fact that he, with a heart of ice, still felt a sense of euphoria at the idea of victory might not have been so common but was certanly intruguing.

Finally finding the road of the mountains, Akumāo observed their layout, realizing that lack of caution could lead to a big fall.

One, two, three leaps were swiftly made, it wasn't particularly challenging, according to Akumāo.

 He arrived at the highest point, jumping onto a floating piece of land barely spacious enough to contain the circus mentioned by the woman, and it appeared quite small.

"It must be here"

 Akumāo said, entering the circus, he found nothing but darkness.

"Let's see..."

Before he could finish his sentence, a click sounded, and a light illuminated a point in the space, revealing a stage right in front of Akumāo.

Laughter echoed from a mysterious voice

 "So, someone has finally decided to challenge me"

The figure illuminated on the stage was, as described, an ordinary-sized clown with a deck of cards in hand, smiling at Akumāo with a hint of malice.

Akumāo couldn't help but laugh at the sight.

"And you're supposed to be the dungeon threat? You seem like nothing more than a joke to me"

The clown felt offended by his words, responding angrily

"You dare call me a joke? You clearly understand nothing about strength, I am Mr. Deck, the boss of this dungeon and the cause of your demise"

When he mentioned "demise" Akumāo stopped laughing, his expression turning serious. 

"You think you can kill me? Perhaps my reputation isn't quite present for you, but aside from that, I'd love to see how you'll manage, if you have the courage, of course."

"With pleasure" replied Mr. Deck

"You see, the story of this dungeon is quite interesting. Once, I was known as a simple clown..."

Akumāo raised an eyebrow, without warning, Mr. Deck began narrating the history behind the dungeon, Despite this unexpected turn, Akumāo decided not to interrupt

"My life was mostly decent until one day it changed drastically. A sorcerer, feeling deceived by me, cursed me. I had a deck with cards that, against my will, caused destruction among civilians, eventually becoming a threat even to the entire world."

Akumāo listened. This must have been why the crystal he interacted with emitted a dark light, but this was probably not the worst part

"No one has ever been able to defeat me, and no one will, you, a mere player of this dungeon, will certainly not be an exception"

 declared Mr. Deck challengingly.

But Akumāo wouldn't back down so easily. Stepping forward, he responded in the same tone,

 "How about we find out who's spouting nonsense?"

"Fine by me, you're welcome to suffer a defeat" said Mr. Deck, selecting a card with a star symbol from his deck

"This is one of the cursed cards, once activated, a part of the cosmos empowers it to cast a curse that knocks you out in a single blow!"

The description was as threatening as it was unsettling, yet it didn't faze Akumāo in the slightest

"Alright, let's see what effect it'll have on me"

Akumāo said calmly

Without delay, Mr. Deck focused magical energy into his card, which glowed intensely, generating a star made of energy that he hurled at Akumāo at high speed.

... As soon as it made contact with Akumāo's body, the star exploded, yet Akumāo showed no signs of being harmed.

"Darn, if you really thought you could hurt me using such a banal spell, you must be really lacking ideas" 

Akumāo remarked.

The clown stood in disbelief, no one had ever resisted the attack before, and the rule of being knocked out in a single blow was a magical law, It was ironic that in Akumāo's presence, such a law seemed to no longer hold.

"W-what...this can't be...you..."

Akumāo was empathetic to his reaction, while Mr. Deck recovered from the shock.

"N-never mind, I have many other cards to play."

Not wanting to waste any more time, another card was drawn from the deck, this one had an entirely different function: it launched an attack that traversed past, present, and future simultaneously, causing the death of anyone struck.

"Die!"

 Mr. Deck activated the card, but its effect seemed to simply fade in the face of Akumāo's power.

Mr. Deck was more shaken than before. 

"It makes no sense, you can't be immune to time."

"You said it yourself, your attack travels through past, present, and future, against a superior being like me, things like time and death just don't affect me" 

Akumāo explained calmly.

The clown's shock soon turned to frustration

"Now, I guess it's my turn."

Akumāo charged his magical fist, causing the ground to tremble with its aura, taking aim, he swiftly struck Mr. Deck, faster than the previous star attack, causing the clown to spit blood from the pain.

"Who...are you?" Mr. Deck managed to utter.

"Call me..." Akumāo withdrew his fist from the clown's body.

 "...demon god."

Mr. Deck collapsed, leaving no trace behind. In his triumph, Akumāo heard a victory sound, akin to those in video games when completing a level

At the same time, a portal opened in front of him, likely leading to a distant place from his current location

"As I expected, it was easy"

 Akumāo stated, taking a step to enter the portal.

"...Akumāo took a step to enter the portal, but when he was about to do so, he suddenly vanished."

"I don't understand. Haven't I already completed this sort of level?" he wondered.

At this point, he would have certainly expected another strange effect to bring back the portal or something similar, but he found it unlikely.

"Well, I can't do anything but get out of here" 

Akumāo said before slowly leaving the place, realizing that surprises were far from over.

He soon noticed he was no longer in a valley of floating rocks but rather on top of a rather large castle.

"Something in this place can't really stay stable for five minutes, huh?"

 he sighed. 

"I guess I'll have to explore further."

He took a big leap to land right next to the entrance of the building.

"Now, what should I do?"

Akumāo suddenly sensed dark magical energy behind him.

"Hm? Who could it be?"

Turning around, he realized he was face to face with a familiar figure.

"We meet again, Akumāo" 

the girl from the forest, or rather the fake forest, greeted him.

"So, you manifest in front of me for a second time, huh?" 

Akumāo put on a mischievous smile.

The girl chuckled at his words.

 "Seems so, but don't think there's any special interest. I appear solely as a source of knowledge."

Akumāo wore a sly smile.

 "I wonder, what's the next thing I'll learn?"

"I won't hesitate to tell you"

 the girl paused for a moment, then continued

"As you've seen, it seems you haven't completed this level yet. The reason seems to be that the previous boss wasn't the real boss of this first level."

"Got it, so that door was just an illusion"

 She nodded.

"That's exactly right. The creatures here are good at deceiving people."

"That explains a lot."

"Anyway, this time I wanted to explain a bit about the social hierarchy."

Akumāo didn't look away. 

"Go on."

"See, even though every world's story is different, social classes are a universal concept in every dungeon."

The girl looked around and continued speaking. 

"There are abstract mages, whose abilities and visions are entirely or almost entirely from spirits, ghosts, and so on..."

"...then, there are earthly mages, the opposite of abstract mages, mainly using physical magic and elements."

"Hmm..."

"Moving on, there are faithful fighters, who instead of using magic, most of the time use martial arts, stronger than they seem..."

"...and finally, there are what we call sentou ,.formidable warriors balanced in both attack and magical speed, never getting tired and always finding a solution to everything. That's it."

"Interesting, so there are these classes where everyone is good at something."

"Exactly, there are many more, but I don't find it necessary to explain them all at once."

Akumāo stopped smiling for a moment. 

"And what class am I to you?"

"Why not find out?"

With a snap of her fingers, the girl created a temporary dimension and brought Akumāo inside. Then she summoned a sentou, humanoid and obviously magical.

"It's more interesting than expected."

The sentou pointed at Akumāo and asked

"Hey, you, what is magic to you?" in a combat stance.

Without warning, Akumāo swiftly attacked the sentou. 

"Magic is the manifestation of an idea... that idea can be anything, as a mage's ideas are endless..."

In the midst of the battle, the sentou punched Akumāo multiple times, but it did nothing.

Akumāo responded by summoning a lance of light and using it as a weapon. 

The sentou quickly dodged Akumāo's attacks and countered with ice spheres.

In response, Akumāo used temporal magic to slow down time around the sentou.

 "...they are concepts we change and bring into reality."

He then used another spell to deflect the spheres and turn them into projectiles.

"For example, as you just saw, I changed the idea behind these spheres..."

The projectiles were promptly avoided by the sentou.

"...and reshaped it my way."

Akumāo created an electro sword and used it for attack, winning with each swing.

Until he delivered the finishing blow.

Slash

"Arghhhh."

The sentou's cries of pain echoed. It went into a rage, causing a climatic change in the dimension with highly destructive thunder.

"It's over now" 

Akumāo exclaimed before finishing it off with a final swing. The sky cleared, returning to normal.

Akumāo turned to the girl. 

"It was sublime"

 she said.

"Yeah, I understand. From your way of fighting and your magical spells, you're on a different level. Maybe you're... an abstract sentou?"

"An abstract sentou, huh? Yes, that could be correct, but are we sure even this isn't a bit too little to describe the demon god?"

The girl chuckled again and took a step towards him.

 "Is that how you define yourself? A demon god? I won't comment further on that because, after all, I'm not omniscient."

"...however, I'm tempted to ask you something else."

"Well, Let's hear It."

"Akumāo, where do you come from? What are your origins?"

 The girl asked, making Akumāo smirk even more with that question.