"We succeed or we blow up."

Rakna stepped out of System Transfer onto a muddy ground with Natsu following him at his feet throwing a cursory look at his surroundings. "The Swamp?" He asked. "My Lord, is this Plateau the workplace you were referencing? I do not understand."

The therian glanced at him and gazed at the gloomy terrain of the Fifth Plateau. He didn't answer the Celestial Blaze and began to approach a sort of a large artificial tree in front of him. It had built-in rails and platforms previously used as watchtowers.

"Why is there such an affluence of dark spirits around this place?" Natsu wondered out loud.

Rakna heard it but didn't answer until they reached a tunnel leading underground, "This used to be a feeding ground for an Abyss Téras," he said as he began to walk down the staircase while the Celestial Blaze froze mid-step.

"A Téras?!" He practically shouted. "Why are we here?! Even I know those abominations shouldn't be trifled with! I don't want to have anything to do with the Téra!"

"Calm down," Rakna rebuffed him. "The bastard's dead. I killed him."

Natsu made a face that screamed 'Is that supposed to comfort me?!'.

"My guildmate made sure that this place was safe before leaving it alone," the therian said and his eyes roamed to the side where he saw one of the stains of blood on the walls of the tunnel. "What happened here was the work of a single Téras. He was acting alone and independently. We don't risk the Abyss targeting us for staying here."

"Even if you say so…" Natsu trailed and then stopped himself when they reached the bottom of the stairs where a large wooden gate had been smashed in. He saw what lay beyond and couldn't help but take a step back. "Wha-what happened here…?" He asked.

Rakna looked around at the massive dark cave barely illuminated by the light emitted by Natsu and which once held an entire village. It was now nothing more than burnt-down rubble. The walls of the cave were destroyed in some places and several craters were scattered around.

"What can I say? I got kinda mad," Rakna said lightly but solemnly. He resumed his walk and Natsu ran after him with mixed feelings.

"All of this damage was caused by you?" He asked.

"Most of it, yes. It happened during the fight."

"Then… whose village was this? I don't see bodies either. What about the residents?"

Rakna halted his march and simply raised his hand to point at something. Natsu followed his finger and widened his eyes when he spotted a large graveyard amidst the ruins. There were at least a hundred tombstones, and nearly all of them were nameless and coarsely made.

"There they are," Rakna muttered and star flashed to the middle of the graveyard. Natsu imitated him with his Flame Step and watched as the therian crouched in front of three certain graves.

One of them was different from the others in the fact that it had a name engraved on it. "Since you seem curious; all of them were Dark Elves. I asked Gray and the expedition force that came to investigate this place to gather and bury the bodies."

"I see…" Natsu whispered. "And… may I ask for whom was this specific tomb engraved?"

Rakna smiled lightly. "A little Night Elf called Vivi Silverlight."

"…was she important to you, My Lord?"

"Not really," the therian said with a huff and stood up. "But she could have been… hah, you would think you'd need to be older to develop a fatherly instinct," he jested and snapped his fingers.

On cue, a swirl of frost energy emerged from the ground and pushed aside the rubbles and dust from all the tombs. Rakna then conjured a magic circle to encompass the entirety of the graveyard and encased all of it in a sort of mausoleum made out of star crystal, but without any energy inside.

"This crystal isn't that strong," Rakna commented after tapping the edifice a few times. "But it will last eternally. All right, Natsu, you're going to help me clean this up," he suddenly said and turned around.

"Huh? Clean up?"

Rakna slowly lifted the corners of his mouth until a grin was formed and right after, his hair and fur turned red. "Yeah, let's turn all of this debris into ashes. I have a house to make. I can't have all of this crap ruin the view."

"…pardon?" Natsu was dumbfounded but before he could raise objections, he saw with a shiver as his newfound Lord ate a frozen heart out of nowhere and released a fiery aura.

"Hoarfrost Blizzard turns into…" Rakna muttered and inhaled. "[Volcanic Tempest,]" he intoned and a red smoke gushed out from his body. The temperature around him increased drastically and after a short moment, the smoke began to swirl and form a tornado.

At the same time, volcanic rocks began to condense inside of it and in no time, a red tempest of magma was raised inside the cave; tall enough to connect the ground and ceiling. The dilapidated and scorched houses took fire once again but this time, nothing was extinguished until nothing remained.

"Come on, Natsu! It'll take a while to thoroughly burn everything. You'll take the borders; I'll deal with the center area. Then we'll clean up the stone and ores," Rakna's voice sounded from inside the tornado, from which Natsu had long taken his distance from.

The Celestial Blaze trembled as he caught a glimpse of a large werewolf within the eye of the red tornado and dutifully began to use his magic to clear out the outer area of the cave.

"Oh! And be sure to not damage the crystal mausoleum!"

Natsu was startled by the additional shout that was far lower in pitch. "Y-yes, My Lord!" He replied and sighed. "Why does it feel like I've been hired as a convenient janitor…?" He muttered to himself and expanded into a giant flame with red eyes.

⠀

* * *

⠀

An hour later, Rakna pulled the last stone debris into his storage and sighed. He cracked his neck and turned Obsidian Blood off. He lit a cigarette and looked around at the dark and empty cave.

Now that there weren't any ruins to cover up his vision, his Eye calculated the exact size of this underground space. For the surface area, it amounted to about 200 000 square meters, which can be roughly translated to 500 meters in diameter. As for the height of the ceiling, it was quite high too for a cavern; reaching nearly 40 meters at the very center, and then gradually decreasing as you got closer to the borders.

"What do we do now, My Lord?" Natsu asked as he flew back from cleaning his area.

"Well, time to bring light," Rakna muttered and bent his neck to look up. "Verias had a formation in place to imitate day-night cycles. I plan to do the same. It shouldn't be hard."

"Shouldn't be hard, he says…" Natsu quietly grumbled. "For your information, my knowledge of magic formations is nowhere near enough to--"

"Just draw over this," Rakna cut him off and used a minimal amount of mana to create the outline of a magic circle with his star energy. He flicked his fingers upward and it stuck itself to the ceiling of the cavern. "There. I'm sure you're not bad enough to fail at following an outline, right?"

"…no, of course not, My Lord. How should I do it? Carving?"

"Use this," the therian tossed a dark blue pen and Natsu caught it with a strand of fire. "It's filled with something called Eion ink. It's also mixed with a little bit of my blood with alchemy. It's a very good formation medium. Now get to work, there's a lot of surface to cover," Rakna said and flashed to the ceiling in a burst of energy and began to draw the runes and shapes whilst dashing at near-unperceivable speeds.

Natsu glared at the pen entangled in his flames as if his current situation was all its fault. He sighed and took on a more humanoid shape before floating away to do his task.

⠀

* * *

⠀

Meanwhile, "Hm, this is the last one," a one-tailed Rakna muttered as his group completed the last Quest they had, which entailed gathering a certain assortment of rare natural chocolates.

"There really are all kinds of clients," Nyx deadpanned as she stared at the stone-like candy in her hand that was being retrieved by the System to complete the mission.

"Some people love to live in luxury for everything," Kaelith said with a sneer. "I would not put it below a random wealthy guy to request the Pavilion to collect these things for a fancy tea party."

"You would know," Rakna uttered with a small smile while the vixen sighed.

"I would know…" She mumbled gloomily.

"Hey, guys, should we check out the Trial?" Allan suggested as he looked at the map. "It's close by and we can test the perks of the Guild."

"Not a bad idea," Rakna concurred. "I want to see if I can do it as a clone too. But before that… let's do a little experiment," he said and looked up at his pet who gazed back with a tilt of his heads.

"An experiment?" Flavia repeated curiously.

"Yes. It's even better now that he developed parallel processing. All right, litt-" Rakna paused and blinked a few times before resuming with a shrug, "Little guy, we discussed this before."

"I don't think he's very little right now…" Allan muttered and was very pointedly ignored.

"Use those five parallel processing heads of yours together to condense your Eion energy," Rakna instructed unperturbed and Pronos nodded. Five of his heads then stretched out from the rest and faced the sky with open mouths. Promptly after, Eion energy in the form of thick smoke came out from his throat and fangs to condense in the spot where the five heads' sights crossed.

"What is he doing?" Evelyn asked as everyone watched. She was the only one in the group who knew about Eion energy to a greater extent since she had assisted Rakna in refining Eion to make ink and also extract Eion Stones with alchemy. "Is he concentrating Eion for an attack?"

"Not exactly," Rakna replied and mused. "Let's see… looks like it will take a moment for Pronos to properly shape it; I can briefly explain it," he said and everyone looked at him. "Do you guys know the basic principle behind a nuclear explosion?"

"Splitting the atoms of a fissile element by throwing neutrons at it," Flavia answered as the others drew a blank. "Energy is then released in the form of heat and radiation while more neutrons are created, which will attack the rest of the element until there's no reaction. Essentially, a nuclear explosion, for the plainest ones, is a chain reaction of atoms being split apart."

Rakna nodded calmly. "The most common fissile elements are uranium or plutonium. They are such that they can sustain a chain reaction. However, regardless of that, any atom can be split. You just need to shoot a neutron into the nucleus at the correct speed."

"Let's say you grabbed a random rock on the side of the road; every atom that composes it can be split and detonated. But unlike fissile elements, splitting one of them will not make a sustainable chain reaction. But that doesn't erase the fact that even an object size of a rock can very well create a massive explosion if all of its atoms detonate at once."

"Okay?" Allan made a weird expression. "Why are you telling us that though?"

"I was coming to it. Basically, what I'm saying is; what if there was a material, or rather, an energy that could cannibalize its own atoms and ignite?" As soon as Rakna worded this sentence, anyone with a functioning mind could infer what was happening.

"Wait, are you serious?" Kaelith uncrossed her arms with wide eyes. She glanced at Pronos who appeared quite strained by the small sphere of energy he was condensing. "Can that thing actually atomically split itself?"

Rakna nodded. "Sort of. Back on Earth, it was a state secret but it's not important here so I'll tell you. The bombs Aurora made, commonly known as Eion Nukes, are actually created by fusing and then splitting the atoms of a condensed agglomerate of Eion."

"Fusion?" Flavia reiterated.

"Mhm. The principle is simple. Eion is normally a very stable energy and it's impossible to use as a fissile element. Not only is it hard to work with non-solid elements but the nuclei of the atoms are impenetrable by any method we know. However, the problem can be circumvented when it is caught in an atomic fusion. Atomic fusion is a reaction that occurs under extreme heat conditions within confined spaces. But even that changes with Eion. When it is being compressed beyond a certain limit, the atoms begin to naturally heat up and a core will be formed among them."

"A core?" Evelyn interjected pensively. "Do you mean the Eion becomes…?"

"'Voracious' would be an accurate portrayal," Rakna stated. "When the first two atoms reach their plasma states and fuse, they will begin to 'eat' the ones around it until there's none left. Once that is done, you have to let it cool down without letting it get in contact with the air. The basic way of doing that was to place it in a vacuum for about 12 hours."

"What about the fission part of it?" Marie asked. "And why cool it down?"

"That's the thing. Both are correlated," Rakna said with a small smile. "You'll see. For now, let's get the compression going," he declared as he saw that Pronos was finished gathering the necessary amount of Eion. "Normally, we would need particle accelerators, a powerful magnetic field, and a gravitational bound but some magic formations and raw mana should do the trick… maybe."

Kaelith groaned. "Why can't I help but think that this is extremely dangerous?"

"All experiments are," Rakna quipped and drew a dozen of runes with a swipe of his hands. "Get ready, little guy. We succeed or we blow up," he joked with a cheery tone and his group could only facepalm.