The Perverted Duo were being vocal about their fantasies again. Once a part of them, forming a trio, Issei just looked on with vague disgust like everyone else did.

School had restarted, and he was not eager to have it cutting into his training time. At the very least, he wouldn't have long before Asia would be sent over for the fallen angels. A week left before the day he had died would come too. He was sure Dohnaseek and Freed had left permanently, but there were a few more signatures settling into the old church. Kokabiel's plan was still in motion, it seemed.

Standing up and leaving the classroom, he made his way back to the ORC again. He was known by everyone in his class for leaving out of nowhere, so no one turned to acknowledge his departure besides the teacher, who did not vocalise his objections.

Once again laying on the familiar sofa, Issei had time to think. Instead of something useful and productive, he couldn't help but think about what he had caused.

What he had let into his home.

When he touched Infinity, he had apparently weakened his mind to the degree that it let the Unknown Concept in, indirectly allowing it into his home. The proof of that was lying in the basement.

The problem came with what injuring Koneko had allowed. She did not have multiple souls occupying her, nor was she nearly as powerful as him mentally or physically. According to Aurora, this concept had directly aimed for her weakened mind, cursing her to never awaken again.

Of course, Issei had removed the curse, and proof of it lay in the form that had awoken when he had entered, and had joined him in his resting place. His prisoner speculated that the mechanical corpse in his basement was being used as a medium, allowing it direct entry through the barrier even though he was no longer vulnerable. Currently, there were plans to have it removed being formed but, knowing the power of a concept, anyone willing to help was not willing to do so without Issei. The boy in question was hesitant to approach it again too, but the only outstanding problem was getting to the lower floor again.

He knew he had to remove it if it was a threat, but it didn't affect the uncanny fear anyone would have felt knowing they may be face to face with a malevolent higher power.

Aurora had told him various other knowledges, mostly answering with "I don't know"or "No". The main part of information he received was not promising. Upon asking about the Unknown Concept, she had revealed that there was a designed entryway into her software. She said she had fixed it when finding herself in the basement, thinking that there was a hacker targeting her. The proposal was that the Unknown Concept was that hacker.

Regardless, Issei was at relative peace right now. He was getting visibly stronger as each day and week passed, and the results didn't go unnoticed to his cohabiters either. He had even made light progress on his adaptation to Infinity, small albeit progress nonetheless. He had hit his target ten times out of three hundred. There was little else to be done except adhere to his past actions closely enough and continue monitoring his training.

Satan knows he wasn't excited to have to see his murderer again, if his memory served him well, tomorrow. Issei had eviscerated her to his best ability last time, and would make the fireworks even brighter this round. Raynare, his first girlfriend, had lured the poor pervert into a half-assed date before piercing his chest with a spear of light. That spear refused to leave his memories, akin to a curse upon him after her death. Every now and then, he still had nightmares of his first passing.

It was unanimously decided by reincarnated humans that death was more symbolic than physical, yet still more physical than the real world. Some had claimed to awaken within flowing fields of eulalia, Chinese silver grass, lying before a tower that pierced the clouds and very sky itself. Only for moments, however, since the method of the Evil Pieces only allowed for rebirth after a short time.

Those that claimed the vision almost always became stray devils within a year. The reasoning was still a mystery when he had died, so even Issei did not know what it meant. To the devils at least, it was seen as a grim omen. It was the only such vision to ever be experienced upon death, so it was speculated that the field represented an afterlife of sorts.

Theories were proposed in droves, but the leading and most commonly accepted answer was that whichever god ruling over that afterlife directly influenced the minds of the returners and drove them to psychosis in the name of bringing them back as soon as possible.

Issei was lucky.

"You're here again? Do you ever plan to go to class?"

"Sona. Not at the moment at least, I'll think about it when you finally let me join the Kendo Club."

"You of all people know it's a female-only club. I don't think any of them have so much as seen you around school, thanks to your escape attempts."

Dammit. All he wanted was to have live targets to practice swordplay on. Kiba was incredible to spar, but facing the same person every time wouldn't help him improve quickly enough.

"Whatever. Why are you here anyway? Rias is still in class."

"We're in the same class, Hyoudou."

"Oh, right. Forgot."

"I'm here for you this time. Need you for practice."

A frightening smile must have painted his face, because Sona actively flinched at the look he threw her.

"Oh, you need me? That isn't how you ask for favours, I think. Maybe if I call Serafall, she can teach you in my place?"

"Please do not. Not to mention, I've been overlooking your absence in classes entirely because of the tutoring."

Issei knew that much. It didn't stop him from having fun though.

"I'll just attend class instead. I know of a very capable Super-Devil that would be more than glad to help you out after all."

"YOU- I-"

"Kidding, don't wake Koneko up. I'll teach you at lunch, need to be home early for research."

"It is lunch."

"No it's not, it's-"

He glanced at the clock to his right. She was correct.

"Oh. Fine, gimme five. Gotta get up first."

"Don't be late please."

As her small figure turned around to leave for the grounds behind the ORC building, Issei shifted himself slowly, patting Koneko on the shoulder as she stirred awake. He couldn't help the smile that slipped atop his face.

"I'm just going to train with Sona, I'll be back soon."

"Mmmm."

With a quick hug, she slumped over on the space he had occupied previously. Issei walked as quietly as he could, moving to follow the Student President's previous pathing.

Said President was waiting rather patiently for him, analysing a magical circle beheld in her palm. The training grounds they were standing in were more than simple, more akin to a clearing within the magically created forest surrounding Kuoh Academy's west face. There were various strengthening circles on the soil beneath them, and there was a small pond not far to his right.

"What kind of training is it this time?"

"I want to show you something."

"So I'm just a target for your magic now? Do I look like a dummy to you?"

"Yes. Besides, it's not offensive this time."

With feint dramatic hurt on his face, Issei watched Sona perform the barrier he had first demonstrated to them. It was not to the level he had done so, but it was incredible nonetheless.

She had reverse-engineered the entire magical circle, barring a few additions and modifications, all from the flow of magic he had shown and the chant to the barrier. At most, it was Middle-Class, but it was a feat nonetheless.

"Wow. You finally did it?"

"It took months. I had to get help from Satan Beelzebub and my sister, but I did it."

"Can you change the properties of it like I can?"

Seeing the barrier rapidly expand and contract gave Issei his answer.

"Beautiful work. It's still really weak and missing more than a few components, but you did it. I'll show you what you're missing, wait."

Walking through her extended barrier like it was the air, he leaned over her shoulder and started pointing out the flaws in her magical circle. She had done quite well, but they were delicate operations. Even the slightest addition could massively increase the output, or change the property of the spell, or stop it from working altogether. These kinds of basic circles were, rightly so, called 'bases'.

They were just a foundation for the user to adapt to their own nature and desires.

"All in all, very well done. I pointed out a lot of potential additions to you, but I think you know to be careful with them. Keep the output at Middle-Class for now, and only go up to High-Class if you're desperately in need."

"Thank you, Hyoudou. Out of curiosity, can I see yours again?"

"Woah. I didn't realise you were like that, President. I'm flattered, but you don't need to make euphemisms with me."

"ISSEI-"

He found himself giggling at his actions. It was too easy to bully her, since she was so uptight usually. Without mentioning that she couldn't do anything back to him, thanks to her nature.

"Kidding, kidding. I'll show you, here."

Issei raised his right foot and slammed it onto the fragile earth, cracking it slightly. A small, red-tinged dome expanded to cover his form. At this size, it was on the higher end of Ultimate-Class. Last year, it had been an average High-Class barrier, including the full chant.

Improvement was more than evident, even on his basic spells. He had far too much time to practice every single one in his arsenal, after all.

"That barrier, it's stronger than I remember. What did you change?"

"It's about a Class and a half stronger. If I expanded it to the size of the school again, it would be strong enough to force every devil except yourself and Rias outside of it. I didn't use a circle, so I'll just tell you what I included."

The mathematics were entirely uprooted. From his last explanation, it had sounded simple enough for Sona's level. This time, she understood the equations and systems behind it, and yet could not comprehend the variables in the slightest.

If she could not rely on her intellect for the understanding, she would have to lean on her natural-born instinct as a devil. Without the maths, he had added another circle around everything to stabilise it, increased the flow of magic directly into the potency and had increased the efficiency vastly by using smaller intricacies.

That much, she could recognise. Only the intricacies and the additional circle would help her, since Sona's magical supplies were not as unlimited as Issei had made his seem.

If he could visualise the circle perfectly though, why could he not show it to her?

After raising the question, he had just chuckled lightly before saying that he was a bit special in how he uses magic itself.

"Special in what way?"

"Well, you're a devil. You have a magical reserve around your navel, that you flow through coils within your body to output it through your hands. You absorb magic slowly from the atmosphere when you rest, but rely on those reserves for the most part. You already know how magical circles work, so I'll skip that part."

"Right. Everyone is like that, though. What makes you special?"

He could confide in her. With a quick ask to keep it a secret, and a confirmation, Issei's skin cracked like glass, falling in magical chunks to imprint onto the soil. Nothing changed.

"An illusion I keep as a standard measure. I'm wearing concealing makeup below, for people that can see through it."

"I don't understand, what are you hiding here?"

The water from the pond flowed towards him, wrapping itself around his hands like a sentient sludge asking for a hug. He leaned into the light puddle within his palms, and rubbed his face.

When Issei raised his face to look at her once more, she saw what he was hiding. Vicious looking red lines covered his face and neck like the markings of a cult. She could see the makeup now, spreading further down his body, through his unbuttoned shirt. He had really defined collarbones.

Sona shook her head, slightly flushed.

"What are those? They look like cuts."

"They are, kind of. I'll ask you a question before I tell you. Which came first, the body or the soul?"

That was an unexpected question for her. She didn't know the answer, since it was never recorded in any book she had read.

"If I had to guess, the body. Why?"

"The soul comes before the body is properly formed. Upon conception, the body is formed over time. On the other hand, when is the soul developed?"

"I don't know."

"The soul appears the second the zygote is formed. It grows naturally alongside the body, but things do not appear out of nowhere. What forms the soul?"

"I don't know."

This interaction, weird as it was, showed Sona how little she knew about things that could be important. She would have to learn more, lots more.

"Magic. I'm sure you know that the bodily fluids involved in conception contain vastly more magic than any other, with exception to the blood and the cerebral spinal fluid. That's why succubi and incubi are the way they are."

"Yes. It's not the most common knowledge, but anyone that's read a single book on the various species knows it."

"Exactly. Upon conception, the magic from the sperm cells that die is excreted slightly, but is mostly kept within. It creates an environment rich in magic for the soul's growth, but the initial fragment is formed from the individual cell of the female."

"So the soul is a collection of magic?"

"Close. In every sense, it is the 'self'. It is what makes you alive, conscious and what gives you a reserve of magic. Upon maturation, the soul treats the magic it was bathed in as poison. It expels it, leaving it in the navel as it shifts towards the heart of the newborn. The magic is left within the previous confines of the soul, which becomes the reserve."

"Okay, I didn't know that either. What does this have to do with you, though?"

"Oh, I was just rambling. You may have seen me use a circle, but I only use them to stabilise a powerful magic or to multicast. The reason I'm special in terms of magic is because all of the spells I have are carved directly into my soul."

That was some weird wording from him. She had only seen Issei use a circle when it was to show someone he was using magic.

"Carved? Do you mean that you were born with every spell you have?"

"No, I mean carve literally. I had a friend directly etch hundreds of overlapping magical circles onto my soul. Instead of forming a circle outside, I can use the one on my soul to do it quicker."

The disbelief on her face was almost magical to his eyes. He knew what she was about to say, because it was exactly what that god had said when he proposed it.

"That's not possible. We're taught that the soul is the single hardest substance within the body, and is so microscopically small that it's impossible to see even by our eyes. How could you etch magic onto it?"

"My friend is a bit special. Anyway, back to my questions. The soul comes before the body, right?"

The skepticism about his friend was clear to him. If there was anyone that could do such a thing, it could only be a god.

"As you said."

"As I said. When you damage the soul, you would directly damage the body since it came first. If you hurt the body, it doesn't do anything to the soul. No matter what you do to it, the effects are reflected onto the body. If you carve magical circles onto it...?"

The realisation set in. As much as she wanted to deny it with her knowledge, Issei clearly knew more on the topic. Not to mention, the evidence was directly in front of her.

"It engraves it onto the body."

"Exactly. The cuts never heal, either. They don't bleed if I'm not using massive amounts of energy, but I still cover them."

Sona had leaned in mid-explanation and was touching the wound directly. It was like the skin had parted, leaving lines of red muscle and blood vessels beneath them.

"Does it hurt?"

"Not anymore."

It did hurt at one point then. He had just gotten used to it. An idea came to her mind.

"Can you use the circles on your body too?"

Issei laughed a bit. Her ingenuity reminded him of himself, since he had tried it before.

"Technically I can. It has a tendency to violently remove all of my skin all at once, though. There's a reason why you can't use any more magic than High-Class when you etch a circle onto yourself."

The thought of suddenly having your skin torn off in one sent shakes down Sona's spine. She wanted to ask about his friend, but if Issei only referred to them as such, then he wasn't going to reveal that tidbit.

"I see. Are you the only one like that?"

"The only one still alive after the procedure. I had to be placed within a partial-stasis chamber for weeks to let my body settle with the damage."

Well, at least there weren't any superhumans like him running around unaccounted for. The damage they could cause would be irreparable.

"Thank you, Issei. Lunch is almost over, so I'm going to go back to class. Are you ready to attend yet?"

He just looked at her with a raised eyebrow. Sona sighed, before waving him goodbye and leaving him in the grounds. She would keep his secret, but needed to do some more research.

Issei just went back to the clubroom and, after picking up the sleeping Koneko, placed himself under her again. He saw Akeno cleaning up the remnants of two cups of tea, saw Rias leaving as he entered, and did not fail to see the looks on their faces.

It was grim, like they had resigned themselves to slavery.

He would have to consult his memories again to find out why. It may have been important, but he had forgotten.