First Summoning

Actually, the reason Roy chose to kill Yaskalos was more to verify if Yaskalos's own soul had grown stronger after devouring a high-grade soul.

The reason he wanted to verify this was because Yaskalos had said that to reach the Quenching Land in the lower Abyss World, one had to be promoted to a Middle Demon. Yaskalos might have known how to get promoted but chose to lie to Roy. Of course, it was also possible that he genuinely didn't know. Regardless, Roy still had a vague feeling that the key to promotion might still be related to devouring souls, and very likely referred to the soul's growth.

Only when the soul's power grew to a certain extent could one become a Middle Demon...

However, unfortunately, Yaskalos encountered a powerful enemy during the summoning process, which led to his death and expulsion. Although he returned to the Abyss World, his soul was damaged, making it impossible for Roy to see any trace of his soul having strengthened. Therefore, he couldn't know for sure if the high-grade soul offering had brought Yaskalos any soul improvement.

Roy didn't know if his guess was correct, but he believed that demons relentlessly pursued souls for a definite reason, and it wasn't simply because they were addicted to the taste.

Devouring souls could help demons accumulate demonic power. This first benefit had been confirmed. Roy's demonic energy attribute had recently returned to its maximum value, and the 0.3 increase remained unchanged, indicating that the soul he had devoured earlier had indeed increased his upper limit.

According to the information in Yaskalos's words, the Demon Heart was the storage for demonic power. This also explained why Roy felt a warm current flowing towards his heart when he devoured souls.

As for Yaskalos's statement that Lower Demons had complex bloodlines and seemed unable to construct demonic power output circuits within their bodies, thus having demonic power but being unable to use it, this did not apply to Roy. He had already confirmed that he could use Telekinesis by consuming demonic energy.

This made Roy realize something: in the System Interface, his attribute displayed [Demonic Energy] instead of [Demonic Power], likely because he, an anomaly among demons, could use more than just magic!

Superpowers, Battle Aura, Spiritual Power, and the like might all be usable by Roy. Therefore, [Demonic Energy] in his attributes was actually a general term, referring to the source of all supernatural energy. This was different from the demonic power required by demons to use Demonic Magic!

With this understanding, Roy's interest was immediately piqued. "That's right, since it's a Private Customization System, doesn't that mean I can customize my own magic and skills? Anyway, the ultimate consumption is Demonic Energy, so there's no need to worry about compatibility issues with Haki or Chakra!"

"So, how do I customize skills?" Roy couldn't help but open the System Interface and look at the [3D] and [AE] function tabs. His intuition told him that these two functions might be the key to customizing skills. However, to his regret, these two function tabs were currently dimmed, indicating that they were temporarily unusable.

"This should be due to missing usage conditions, right?" Roy unconsciously swayed his tail as he thought. "Given that the system requires the cost of souls for everything, the usage conditions for these two functions should also be related to souls! And, perhaps it's High-grade Souls! Yes, High-grade Souls!"

Roy's spirits immediately lifted. He had been wondering why there was a distinction between low-grade and high-grade souls if low-grade souls could also be used to modify his body in the system interface. Now he finally understood: High-grade souls were for advanced applications within the system!

Thus, Roy now had a goal: to obtain High-grade Souls to verify his hypothesis.

Extending his claws, Roy grabbed Yaskalos's corpse and, with some effort, dragged it down from the altar. Yaskalos was massive, and he couldn't let him block the altar. After clearing the altar, Roy began to wait nearby.

Since his hatching, Roy had only captured Low-grade Souls in this Upper Abyss World. It seemed that obtaining High-grade Souls in the Upper Abyss was a slim hope. Even if there was a chance, it was likely very low. So, Roy decided to shift his focus to other worlds connected by the Abyss Gate.

Roy didn't wait long. The magic array on the altar glowed again, humming as it activated. In the void, a Bloody Smell began to drift out.

"Hmm, good!" This meant that the Summoner in the world on the other side of the Abyss Gate was still using blood to lure demons. This was good news for Roy.

For Roy, he didn't want to stumble into a world with high combat power and end up like Yaskalos, killed and expelled. Instead, this method of attracting demons with blood was the best choice. This was because the Summoner on the other side was either an amateur in a world with underdeveloped occultism, or they didn't have a high demand for demonic power and only wanted to attract Low-Rank Demons to complete minor tasks.

Either way, for Roy, who was being summoned for the first time, it was a good choice.

But Roy waited a little longer. He wanted to judge the Summoner's magical power strength based on the activation time of the magic array.

During the time Roy was waiting, a Little Demon was attracted by the Bloody Smell. When this Little Demon climbed onto the altar and saw Roy, a competitor waiting nearby, it didn't know where it got the courage, but it bared its teeth and threatened Roy!

Facing such a suicidal Little Demon, Roy casually swatted it away! He smashed the Little Demon's head!

Casually picking up a Low-grade Soul, Roy put it away and stepped into the magic array. He saw the magic array's light about to disappear, realizing the Summoner's magical power was insufficient, and only then did he confidently Respond to the Summon.

The Abyss Gate opened, and mist enveloped Roy's body, bringing him a very peculiar experience. Standing within the Abyss Gate, darkness surrounded him on all sides. Only from above did a sliver of light emanate – the exit to another world. Roy, standing in place, began to fade into nothingness.

His body seemed to transform into a beam of light, soaring towards the exit above. Upon reaching the exit, his surroundings dissolved into a blinding brilliance, and his body began to reappear.

As the dazzling light faded, Roy found himself in an unfamiliar place. A cacophony of shouts reached his ears.

"Suc... Success!?"

"A demon has appeared!"

"So... so terrifying! Retreat quickly!"

The chaotic sounds grated on Roy, making him irritable. He looked down and realized he was standing within a Magic Array. This array bore some resemblance to the ones on the altars in the Abyss, but it was etched into the ground. Flowing within these grooves was red blood, which outlined the Magic Array like ink.

Around the Magic Array, four Human Skulls were placed at equal intervals. Burning Candles were lit atop these skulls. Furthermore, between the skulls, several Glass Jars filled with internal organs were positioned, and a putrid odor permeated the air.

A group of people clad in Black Cloaks stood far outside the Magic Array, gazing fearfully at Roy, who had appeared within it. Judging by their panicked expressions, they themselves could hardly believe they had actually summoned a demon...

Roy felt terrible. During the summoning process, he felt as though something had been added to his soul – it seemed to be the Ouroboros Mark. However, this mark, meant to protect his soul from annihilation, was causing him a slight sense of dizziness. This dizziness had yet to subside when he was assaulted by the nauseating stench, compounded by the chaotic voices around him, all of which greatly annoyed him.

Therefore, Roy couldn't help but open his mouth and let out a huge roar at these people!

"SHUT UP!!! WHO THE HELL SUMMONED ME!???"