The Prince of Sloth [DxD]

A certain Castle – somewhere in the Belphegor Domain, Underworld

"Now that you've learned the structure and components of a magic circle—and can even draw one—let's move on to how to actually produce a magical phenomenon using them," Rudiger said, sketching a magic circle on the ground with chalk. He continued, "There are two ways for a magic circle to generate a phenomenon," then paused briefly, while starting to draw a second, identical circle, he added, "The two methods are distinct on two aspects… the first aspect is how we supply that energy to the magic circle for its activation."

After a brief pause, during which he finished drawing another magic circle, making a total of three, Rudiger went on. "The first method is to channel energy directly into the magic circle, like this…" He placed his palm at the center of the first circle and began injecting Demonic Power into it. The circle started to glow, and a sphere of water began taking a form above it.

"I see…" Seir said, nodding, unsurprised by this demonstration.

Rudiger ceased the flow of his Demonic Power as the sphere of water disappeared and moved to the second circle. Taking a small vial from his coat pocket, he continued, "The second method is to use a catalyst containing magical energy." Opening the vial, he poured out a black liquid that spread through the lines of the magic circle. "There are many possible catalysts—like dragon's blood, Phenex tears, a witch's concoction made from multiple ingredients, or simply a magic stone extracted from demonic beasts; melted into a catalyst using alchemy, as I am using at the moment. The key point is that the catalyst must contain sufficient magical energy to activate the circle and produce the intended phenomenon."

"Hmm… alright," Seir murmured, watching as another sphere of water materialized from the magic circle. Then he cast a doubtful glance at the third one, thinking, 'If there are only two methods, why do we have a third circle for this demonstration?'

Noticing Seir's confusion, Rudiger asked, "You're wondering what the third magic circle is for, right?"

"Yes, Master Rudiger," Seir replied, asking, "Are there three methods?"

Rudiger chuckled, shaking his head, "No… there isn't a third method… although you can say it's a third method if you want to, some mages certainly call it this method the third method… but I don't consider it the third method. To me, it's just an extension of the first two methods…" and moved toward the third circle. From his coat pocket, he took out another vial and emptied its contents onto the circle, causing it to glow faintly—much dimmer than the second magic circle. Seir frowned in puzzlement.

"As you can see, this circle hasn't reached full activation using just the catalyst," Rudiger explained. Pausing, he asked, "So, what else can I do to make it activate?" Setting aside the empty vial, he bent down and placed his palm at the center of the circle. "Just add your own energy."

He began channeling his Demonic Power into the circle and continued, "Often, the catalyst by itself isn't powerful enough—it might not contain enough magical energy. And sometimes, our personal reserves alone won't meet the circle's requirements. So, in those situations, you combine both: the catalyst's energy and your own demonic power. That approach helps tremendously."

"Makes sense…" Seir nodded in understanding. Suddenly recalling something Rudiger had mentioned earlier, he asked, "What's the second distinction between those two methods?"

Rudiger smiled, pleased that Seir had caught that detail. "The second distinction lies in the final result." He returned to the first magic circle and, after injecting it with energy once again, explained, "While the outcome of the first and second magic circles may appear similar, they're actually quite different. The difference is in the level of control."

He paused as the circle condensed into another water sphere, then continued, "Because I'm directly providing energy to this circle, I can control its output. In other words…" He focused on the water sphere, causing it to move slightly. "…I can manipulate the result—in this case, the water sphere—according to the properties I set using the five variables, and I can make further calculations as I go. Essentially, I can continue to adjust and refine the spell while using this method."

Rudiger then turned to the second magic circle. "Because I'm not providing energy directly to this one, I can't control the result once it's formed. The magic sphere will only perform the actions encoded in its equation, and I won't be able to influence it further."

As he spoke, the glow of the second circle began to fade. Pointing at it, Rudiger added, "And as you can see, once the catalyst is consumed, the magic circle ceases to function." Sure enough, the water sphere vanished as the circle's light died away.

Seeing this, Seir asked, "So, you're saying the second method isn't as good as the first one?"

Rudiger chuckled at Seir's response. Rather than answering directly, he asked, "Tell me, which is the better chess piece—a [Knight] or a [Bishop]?"

"Huh?" Seir blinked in surprise, then replied, "Neither is better. They're both equal in value."

"If that's the case, why are they categorized differently?" Rudiger pressed.

"It's because they serve different purposes," Seir answered, gradually realizing what Rudiger was getting at. "Master Rudiger, you mean the two methods of activating a magic circle also serve different purposes?"

"Exactly," Rudiger nodded with a satisfied smile and began explaining, "While the first method gives you more control, it also keeps you stuck in one place. You have to stay here, stand inside the magic circle, and continue providing energy to the circle. If you stop, the circle immediately stops working." To illustrate his point, he removed his hand from the circle, cutting off its energy supply. The gathered water vanished at once.

Rudiger then gestured toward the second magic circle. "On the other hand, that circle, which I activated using the second method, continued producing its result even after I stopped paying attention to it and moved to the third circle. It only stopped when the catalyst was fully consumed. In other words, if you use a catalyst powerful enough not to run out right away, you don't need to remain permanently connected to it."

After a brief pause, he added, "Certainly, I didn't have direct control over the water sphere it produced, but if I were to make the right calculations beforehand, write the proper equation for the phenomenon I want, and provide a suitable catalyst, it will generate that phenomenon even in my absence."

"Is that so…?" Seir murmured thoughtfully.

Rudiger went on, "Neither method is inherently superior; they simply have different uses. For example, we Devils commonly rely on the first method for teleportation, while the second method is more often used by human clients when they summon us Devils."

"I see…" Seir nodded.

"Now that everything is clear, let's move on to what you have to do," Rudiger said as he began to draw several magic circles on the ground. He started with the simplest one—featuring a three-pointed star—then moved on to a four-pointed star and finally drew a Hexagram.

When he finished, he turned to Seir. "Including the Pentagram circle, these four magic circles each present a greater challenge than the last." Explaining that part, he continued, "I want you to practice channeling your Demonic Power into each circle to activate them and understand how Demonic Power flows through them."

As Seir prepared to begin, Rudiger added, "Also… start with the simplest one."

"Understood," Seir replied. Stepping into the first magic circle, his body became enveloped in a violet demonic aura as he began channeling his Demonic Power into it, activating the circle.

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A certain Castle – somewhere in the Belphegor Domain, Underworld

"Now, let's move on to the final step of using magic through a magic circle," Rudiger said calmly, standing before Seir. "From the very beginning, our goal has been to cast magic without relying on pure imagination. So far, we've studied different magical equations, gone through the calculations and computations, and learned both the structure of a magic circle and how to construct one. We've also covered how to channel Demonic Power into a circle, how it operates, and how to control the phenomena it produces.

"The last step is to combine all of this knowledge and create a magic circle in midair—without relying on any surface—maintain its structure and cast magic from it," Rudiger explained. "After all, during battle, you won't have time to sit down or take a break to draw a circle on the ground and then channel magic from it. So, you must be able to form a magic circle without depending on any surface and channel magic from it."

Seir nodded. "Yes…"

"But the question is," Rudiger continued, "how exactly do you create a magic circle in midair? That is, how do you draw a magic circle in the air?"

Seir responded promptly. "We shape our Demonic Power in its rawest form to form the magic circle's required geometry in the medium."

Rudiger nodded in agreement. "Exactly. That's precisely what needs to be done," and added, "And frankly, this is not such a difficult task… just some good control over the demonic energy is needed along with some attention to detailing to not mess up the design or detailing of the magic circle… and it shouldn't be such a difficult task for you since you have been doing this subconsciously all along as you produce any supernatural phenomenon using your imagination…"

"That's right…" agreed Seir. He has been using magic since he was just a few months old infant.

"Well then… what are you doing there standing… let's get to it…" said Rudiger adding, "Practice creating different magic circles… then create different magical phenomena through them while controlling their various properties…."

"Alright… got it…" said Seir as began to practice how to create Magic Circles using raw demonic power

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At a certain training field – somewhere in the Belphegor Domain, Underworld

"Fireball!"

Chanting the name of the magic spell, Seir, who was floating in the sky enveloped in a shroud of violet Demonic Power, raised his hand. From the Heptagram magic circle already circulating in his palm, two small spheres of fire, about four centimeters in diameter, emerged.

"Now, to make adjustments to the 'Fireball,'" Seir murmured, his brow furrowing as he began running calculations in his mind. Carefully, he altered the values of various variables assigned to the magic circle. As he did, the violet magic circle in his hand shifted and morphed. When the changes were complete, he could feel his Demonic Power being consumed by the Magic Circle as the once-tiny fireballs rapidly expanded, growing from a modest four centimeters to massive fire spheres, each with a diameter of a hundred meters.

And the best part? Seir had created these fireballs—more than three times larger in diameter than the one he demonstrated to Rudiger six months ago—while using only half the amount of Demonic Power.

'This is a sixfold improvement, which is a significant progress. With this efficiency, I can now cast six times the number of spells compared to what I could manage just six months ago...'

Lost in the excitement of his progress, Seir suddenly felt his hand trembling. "Aah... these are indeed heavy," he muttered, his voice strained as his focus returned to the two massive fireballs he was struggling to hold.

The sheer weight was overwhelming, and the intense heat radiating from them was nearly unbearable.

'Any longer, and it would undoubtedly scorch my hands.'

Reacting swiftly, Seir hurled the colossal fireballs toward two different distant mountain peaks–more like made them fly in those two directions by changing the values accordingly. The moment the two fireballs struck, they erupted in a devastating blaze, engulfing both the entire summits in an inferno. The intense heat melted the surface of both the mountains, transforming them into a torrent of molten lava that began cascading downward.

'The resulting effect is also much better…' thought Seir to himself as he distanced himself from the two mountain peaks that had turned into an inferno.

By the time the flames subsided, the mountain's peaks had completely vanished, leaving behind circular expanses of scorched earth as if a meteor had slammed into them just a moment ago and obliterated them entirely.

"Now, let's try other spells…" he muttered, creating yet another Heptagram and channeling two Tornados from it. The resulting devastation far surpassed that of the earlier spells, yet he paid it little mind. Instead, he continued unleashing more and more magic, cycling through every element he could and even simpler spells he was capable of casting.

To an ordinary observer, his training would have looked like a scene straight out of hell—each spell bringing about greater destruction. Seir, however, remained focused on pushing his limits. He pressed on, casting spell after spell, until he had consumed more than eighty percent of his Demonic Power reserves.

"Hah… hah…" he panted, wiping sweat from his forehead. "My efficiency and power have both grown immensely, and it's so much easier to cast these spells now… It's clear that the past six months of training have paid off."

With such a thought, he paid no attention to the devastation he had caused and instead flew over to where Rudiger and Roygun hovered in the sky, both observing him intently.

As he approached, Roygun ruffled his hair with a proud grin. "That was splendidly done, kiddo."

Seir accepted Roygun's praise with a proud chuckle. "Thanks, sister," he said before turning to Rudiger. "How did I do, Master Rudiger?"

Rudiger, who was naturally more critical, still nodded in approval. "Very good. As expected of a genius. With this, you've officially become a 'Magician,' and it took you very little time. Granted, you're still a bit young to be one… but I suppose that's what being a genius entails." He paused, then added, "From here on, you need to focus on expanding your knowledge base and trying out various kinds of magic."

Upon hearing this, Seir frowned. "Does that mean our classes are coming to an end?"

Rudiger shook his head. "No, that's not the case. The lessons will continue because so far, all you've learned is how to cast magic using a Magic Circle. Being able to do that doesn't automatically make you a full-fledged mage. At this point, I'd classify you as an apprentice mage who's still in training. From now on, we'll focus on different aspects and types of magic, among other topics." He paused again, then added, "However, the number of classes will decrease. Probably once a week. You'll have more time for self-study and personal exploration since that's the only true way to master magic and progress in it."

'So, the number of classes will decrease, huh? That means I can focus my attention on other things as well…' thought Seir.

"I see," Seir said with a thoughtful nod, then bowed politely. "I look forward to continuing our lessons."

Rudiger smiled. "Yes… me too," he replied, glancing at the setting sun. "But we'll have to end today's class here. I have a Rating Game coming up, and I need to prepare for that."

"Ah, yes, I understand," Seir said with a nod. "Best of luck with your match, Master Rudiger. I'll be cheering you on."

"Thank you," Rudiger said, smiling in appreciation, before turning to Roygun. "Well then, I'll be taking my leave."

Roygun responded with a grateful smile and a wave. "Thank you for always making time to teach my brother, Rudiger."

Rudiger offered a polite bow. "It's my pleasure," he said, and with that, he vanished through a teleportation magic circle.

With Rudiger gone, Roygun turned to Seir. "Shall we head back to the castle as well?"

Seir nodded. "Yes…"

Since the castle wasn't far away, they decided to fly instead of using a teleportation circle, especially because the setting sun on the horizon was a sight too beautiful to miss.

About halfway to the castle, Seir suddenly called out, "Hey, Roygun…"

"Yes, Seir?" she asked, turning her gaze toward her little brother.

"Now that my lessons with Master Rudiger will only be once a week, I want to focus my attention on something else as well." Said Seir.

"Something else?" Roygun repeated, looking a bit puzzled. "What do you mean?"

"I'm talking about [Crack]," Seir replied. "You know—the trait we Belphegors inherently possess."

"Oh, [Crack], huh?" Roygun murmured.

"Yes. After all, I'm the next heir of the House of Belphegor," he said with a nod. "I need to master it, don't I? Without it, I can't really call myself the next heir. And right now seems like a good time."

"Hmm… that's true," Roygun acknowledged. "You won't be as busy now that your classes are to once a week. But are you sure about this? I suggest taking a break for a while."

"Take a break?" Seir repeated, sounding surprised.

"Mhm." Roygun offered a reassuring smile. "Give yourself some time to rest, and then we can start your training for [Crack]."

"Well…" Seir hesitated, clearly torn.

"It's never good to overburden yourself, you know," Roygun said. "What's the rush? It's not like you need to master [Crack] immediately. Besides, if you take a small break to reinvigorate your learning spirit and relax your mind, your learning efficiency will increase."

"While, you do have a point," Seir sighed, "but I still want to start learning [Crack] as quickly as possible."

"I see," Roygun said. "How about this: take a two-month semi-break while keeping up with your normal lessons, which will now occur once a week, during this time spend time with Father and Mother to recharge, and prepare to participate in the upcoming Extra Demon gathering. After those two months, I'll teach you [Crack]. Two months will fly away in the blink of an eye, it isn't long at all—it's just enough time to refresh yourself."

'From a Devil's perspective, that is…' thought Seir internally, but after pondering over her words for a moment, and taking into account the matter of the upcoming Extra Demon gathering that he would probably be participating in as well, he decided not to argue, and agreed, "Alright, let's start in two months."

"Yes, we will," Roygun promised ruffling his hair. "Now, let's head back to the castle and take a bath before joining Father and Mother at dinner."

"I could use a bath, too," Seir nodded.

"Yeah? Come on then, let's go. I'll shampoo your hair," Roygun said, smiling.

"Okay," Seir agreed, and they quickened their pace, heading back to the castle for a warm soak together.

As they were hurrying along, Roygun remembered something. "By the way, Seir… that child Cleria, from House of Belial, was asking about you. You should write to her or something."

"Huh? Oh, right… I guess I will," Seir replied, recalling his previous interaction with hers, and thought to himself, 'Though rather than writing to her… wouldn't it be better to connect via the communication magic circle? Yes… let's do this… I will spend some time to figure out how to contact over a long distance over a communication magic circle… then speak to her…'

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Author's Note:

That's it for this Chapter. Enjoy reading it.

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