The Demon Monarch System

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"Roarrgh," Arleo released a bestial roar as a tinge of golden light permeated his crimson aura. However, in comparison to his crimson aura, the appearance of the golden hue was faint. Admittedly, the difference between his two attainments in Sins was great, or at least that's the impression his actions gave.

While it wasn't as exaggerated as he made it seem, the reason for the unequal proportions was due to Arleo's fears. After all, he had attempted to use both of his Sins simultaneously once before. But, the result was unsatisfactory, to say the least.

As Fuhrer revealed once before, using two Sins at once was dangerous without a sufficient medium. Especially when it came to two hyperactive Sins like Ira and Superbia. A combustion would occur if they slipped past the boundary that forbade them from coming in contact with one another. 

Alas, Arleo wasn't privy to this information back then. He attempted to wield his two Sins simultaneously and his actions resulted in a devastating outcome. The incident forced him to be bedridden for a month while his two Sin Vessels recuperated. However, he was lucky because most demons who attempted that feat possessed substantial Sin volume.

The deeper the reserves, the stronger the combustion. But, as a young demon, Arleo's Sin volume at the time was insignificant, so the result was only being damaged and not death. 

Fortunately, Arleo learned from his mistakes. Furthermore, the mistake gave him some insight into the relationship between sins. Although they were antagonistic, there was an improper way to bypass their volatile behavior and preserve the safety of one's Sin Vessels.

As long as he didn't allow the supplemental sin to be in equal parts, then the chances of a combustion occurring reduced greatly. And, even if it took place, the diluted ratio resulted in a bearable shockwave.

Therefore, Arleo was willing to take this chance against Apollo, because with his current state, the chances of the combustion happen was next to zero as long as he monitored the two outputs closely. Not only was it to show that he wasn't inferior, possessing dual sins of his own, but Apollo's usage also gave Arleo some inspiration. 

'I can feel it. Although his Sins are being used equally, they aren't blended. This must mean he is sparing a substantial amount of mental strength to keep them at bay. That, or he's aware of some secret to make dual utilization simplistic,' Arleo thought to himself. 

He wasn't sure of Apollo's tactics, but he was sure that someone of Apollo's talent wouldn't recklessly endanger themselves just to prove a point in a small evaluation. At least, that's what he thought until he realized that he harbored even greater intentions.

Finally, Arleo's aura climbed to a new height as a tinge of gold overlapped his already terrifyingly sharp claws. The change caused a sense of dread to pulsate in Apollo's mind.

'That isn't something I'd like to suffer an attack from,' Apollo thought. As a precaution, Apollo agitated a large portion of the energy within his Sin Vessels.

〈System: «Diabolic Heart» is being stimulated.〉

〈System: «Dauntless Vertebrae» is being stimulated.〉

〈System: «Dual Partial Transformation» activated.〉

As they sounded, a Sin Vessel was in short the organs of a demon that were optimized to contain Sin. In Apollo's case, each of his Sin Vessels were indicated by the placement of his stigmata's core.

So, in addition to activating his stigmata, Apollo once again took on the mixed form of a Suprana and Iraym. The divided form took the Archdemons of the Dakea Stronghold by surprise. After all, each of his forms were a rarity in this day and age. So witnessing a demon unleash both forms and do so in such an odd way was a baffling sight.

Regrettably, neither Xonnomor nor Gallmath could spare this matter too much attention, as Fuhrer and Geneva were more than just worth adversaries.

However, they didn't need to. Arleo alone displayed enough shock from everybody present. After all, he was the one closest to the spectacle. Besides, being so close allowed him to sense something else.

"What… Isn't this aura practically on par with an Archdemon?!" Arleo muttered with widened eyes. As revealed when he used this form on Valac, the simultaneous effects from both forms causes Apollo's strength to receive a sizable increase in Apollo's strength.

In fact, just his strength alone increased by 50%!

In other words, while in this form, Apollo's strength was close to 3,000. Not too far from equaling an Archdemon at its peak levels.

All of a sudden, Apollo's powerful change resonated with Arleo's innate thirst for battle. A sharp glint appeared in his eyes while his intrigued smile exposed his amplified fangs.

Bang!

An explosive noise occurred as Arleo performed a mad dash towards Apollo. The previous notion of limiting the damage done to the stronghold completely escaped Arleo's thoughts as he destroyed the ground as a result of his actions.

His rapid acceleration caused him to turn into a blur of crimson-gold before appearing before Apollo with a wild visage. Additionally, the claws surrounding his open hand seemed to grow two times larger as he floated before Apollo for a moment.

In response, Apollo's eyes narrowed as a sharp aura billowed from his body. Immediately, Apollo switched from using the Demonic Massacre Wave to using the potent attack power of a Nether Severance.

An absurd clash took place, followed by a whirlwind of malevolently sharp aura that splintered everywhere. Although this was one of Apollo's strongest attacks, it wasn't enough to overpower Arleo.

Fortunately, although it wasn't enough to overpower him, that didn't mean he suffered a loss in this exchange either. To Arleo's surprise, the two attacks neutralized each other, granting neither side any advantage.

Still, Arleo was shocked by the outcome as well as Apollo's ability, 'Wasn't the preparation of that attack a little too quick for a Greater Demon? That convergence rate was identical to mine… How odd.'

Afterward, the two clashed numerous times with neither side able to capitalize on openings.

Therefore, the more he fought against Apollo, the more Arleo found himself being intrigued by Apollo's existence. Perfect utilization of Sin without forcing a cataclysmic combustion, and now a movement rate of energy on par with an initial Archdemon.

It was simply unprecedented!

Though he was shocked, Arleo didn't forget to throw in a surprise attack by conjuring another strike before Apollo could recover from their last clashes. Unlike Apollo, who gathered himself to execute the Nether Severance, Arleo wasn't using an additional technique.

These claws were simply an innate technique that consumed his supply of Sin Energy continuously without any extra invocation. Depending on the intensity of the stream provided, the claws could either be stronger or weaker. 

But, what Arleo didn't know was that Apollo didn't need a period to gather his energy either. As long as Apollo achieved a certain mastery of a technique, the system stored the information and granted Apollo the ability to invoke instant execution. 

In short, Apollo possessed a type of cheat code, but it was only accessible if Apollo proved he deserved that privilege by completing the requirements.

Therefore, when Arleo launched yet another claw attack, Apollo retaliated with another Nether Severance, producing an identical effect, except this time Apollo finally used the aftereffects of the collision to create some room.

'Despite my unique perception, I'm just barely keeping up with his movements,' Apollo thought to himself. Afterward, Apollo's expression became solemn as a third and then fourth energy leaked from his body. They both carried faint traces of omnipotence and desire.

For a moment, Arleo felt a sense of dread accompanied by reverence, but this was quickly shaken off. Still, that short instant was enough to raise some awareness. 'What type of power is this?'

Unlike the ancient demons, there were some demons who weren't privy to the usage of auras since it was a practice used to envelop Sin. Plus, it was a path introduced to the demons by the Monarchs. 

But, with the remnants of his practices being scarce, knowledge about these matters was limited. Especially for young demons such as Arleo, who learned all they knew from instinct as well as trial and error.

Just as Asteroth stated before, the standards of the demon suffered immensely over time. As of now, if they were compared to the other 3 upper races, their place as the contenders for the strongest would undoubtedly be revoked.

Not to mention, Apollo's current actions of employing over four energy produced pure fear!