Two days later, Adrien woke up completely refreshed. Even though he could go without sleep for an extremely long amount of time, he still liked sleeping. It was because even though it didn't really affect his body, his mind would become sharper and the brain fog he would have accumulated over the previous day would dissipate. It was like he cleaned his mind palace from the clutter and it became easier to navigate in.
He stood up, went to his closet and took out the school uniform he had received a few days ago, it was a normal navy uniform with a red tie. His classes would start at 8 AM so he left his house at around 7:30. He didn't see Mahiru so she might have went earlier.
He got to school five minutes before the bell while eating a croissant he had bought on the way. The school looked normal, nothing special. He looked around for a few seconds, trying to sense any strange energy, but found nothing. So he just went to his classroom, Class 2-B. His neighbor was a first-year student, so they were not in the same grade.
What he didn't expect was the reaction he got from his classmates, apparently his blonde hair and western like appearance caused quite a stir, especially with girls.
"Wow he's so tall!"
"Look at his eyes..."
"His hair is so cool..."
Unlike the girls, the guys were glaring at him like they wanted him dead. He ignored them completely and sat in the empty seat in the middle row by the window. The classes were extremely boring to Adrien, everything related to science was very easy to him since he probably knew about them more than the professor.
Social studies and languages were also not a problem since he could memorize anything by reading it a few times. So in class he just opened a book and read, he was reading a light novel right now.
The day passed uneventfully, it was a normal school day, though he was at first interested to live what he has seen in Anime, it ended up being extremely dull.
The next day was the same, but this time he was working on an ability and thinking on how and when to use it. The third day he had PE, they played dodgeball and he absolutely annihilated class 2-C by himself. He also got nicknamed, 'the prince' since he gave the vibe of one. And well they weren't too far off, he was a member of imperial dynasty of some sort.
At night Mahiru came to his house and they ate dinner together, but today something was up with her, she had a sad and forlorn expression on her face. Her usual golden eyes that shined and brought warmness were now cold. She was cooking in the kitchen when Adrien flanked her from behind and ruffled her hair.
"You okay Mahiru?"
"Yeah, I'm alright, just under the weather a bit"
"I see, you can talk to me if you want, I'll listen."
"Thank you, but it's alright I'm really okay."
Adrien didn't push the matter any further, if she didn't feel like talking about it then she didn't need to, he wouldn't force her. He returned to the living room, took his phone and started searching for something. After he was done, he helped Mahiru a bit, preparing the plates and drinks. Then they dined in silence and she returned home after that.
It was 10 PM, Adrien was sitting on the couch lazing around, watching Naruto. Suddenly, he felt a demonic power output from far away. From what he could sense, the output wasn't that strong, a middle-class devil maybe. He wasn't sure that it was a stray devil since he didn't feel any intent from the power.
"Should I go check it out? Nah, It would be stupid, I would just reveal myself. And who knows maybe it's a trap set to catch me." Adrien decided to ignore it, he was just a regular dude right now. And if it really was a stray devil, they would send someone to kill it soon enough.
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"It's useless, he wouldn't reveal himself like that", Seekvaira said sighing in resignation.
"Yeah but what makes you so sure he's in Tokyo?". A mature voice, that of a woman asked.
"First of all, Adrien decided to leave just after Lord Lucifer told us about the appearance of the red dragon emperor, and knowing him he would have felt that 'fun' stuff were about to happen in Japan so knowing him he would decide to go there"
"Yeah but why Tokyo, he could have gone to Sendai or Kobe or anywhere else that isn't directly part of a territory, he could just teleport to Kuou."
"He would yeah, but it would be too far away from you. Tokyo is close to Kuou, so he would sense if any happened easier and even though it has a few devils here and there, none of them would be able to find him anyway."
"They wouldn't? I've only met him a few times, and I've only heard rumors but is he really that strong?", the woman's curiosity was increasing. She had only seen Adrien a few times when he came to Kuou to annoy her best friend, laze around then go back. She had never seen him fight or train or do anything normal devils do.
The rumors she heard were even worse, he was nothing but a trouble maker and did whatever interested him in the moment. He would disappear from the estate, cause trouble, then come back. He would mess with high ranking devils and Gods to kill his boredom. Every time he leaves Agares island, Lord Agares becomes sleepless in fear of what he was about to do.
And this time was no different, so his family asked Rias Gremory for help and she sent her queen Akeno Himejima with Seekvaira to try and find him.
Seekvaira chuckled at Akeno's question. "Strong doesn't even begin to describe it... have you heard the story about Lord Sirzechs Lucifer's birth? He had so much demonic power that the natural energy every devil leaks was enough to destroy the entire room he was in."
Akeno nodded, "Yes I've heard of it from his Lady Venelana herself, the power of destruction leaked and destroyed the furniture around him."
Seekvaira gave a small smile, "Yes, but that wasn't the only abnormal birth that the underworld has seen, you know. When Adrien was born there was no energy leak atall. Father even thought that he had no demonic power."
Akeno blinked, her violet eyes widening in clear surprise. "What... how is that even possible? Even the Great Satans cannot perfectly control the demonic power leaking from their bodies."
"It's his body, It's able to contain demonic power perfectly".
"It's kind of unfair isn't it", Akeno gave a weak smile.
Seekvaira gave a small, helpless shrug. "You tell me. I have never once managed to defeat him. Adrien uses his power with absurd precision. Even if two people possessed the same amount of demonic power, where I could use an attack ten times, he would likely use it sixty".
"Wow... that's crazyyy!", a voice came out from behind him. "So he's even stronger than the prez?"
Issei, who Rias had sent with Akeno so he can watch how she works, was silent until now. But he couldn't stop himself from reacting to the conversation he was hearing.
"But I didn't really understand how it works", he continued.
"What works?" Akeno asked him puzzled.
"Well, you said his body doesn't leak demonic power... but all Devils do?"
Even though he had asked while looking at Akeno, it was Seekvaira who answered.
"All living beings leak energy," she said. "Demonic power, holy power, life force, it does not matter. The amount is usually so small that you would never notice it right away. Only after it builds up, or rather after enough of it has been lost, does the effect become clear. I will give you a simple example. After you were reincarnated as a Devil, you immediately felt stronger, did you not? Your stamina increased, your endurance improved, and your body became more capable overall. That is because the demonic power within you began supporting your body alongside the energy it naturally produces from food, rest, and its normal functions."
She paused for a second before continuing. "But think about it. Even if you do nothing and never use a single spell, why would you still grow tired over time? It is because demonic power is always leaking little by little, and your body is also constantly spending energy just to keep itself going. If that lost demonic power is not replenished, the body starts relying more and more on its own stored reserves. Once those reserves begin to run low, your condition worsens, your stamina drops, and your body weakens. But if that demonic power didn't leak at all, then it would keep supporting the body almost without interruption. In that case, a high-class Devil could remain active for an absurd amount of time without truly wearing down."
"But what about his power? How does that even make sense? I get that his body barely leaks demonic power, but what does that have to do with how crazy his control is when he actually uses it?" Issei asked. And the question was not dumb. Where was the connection between his body not leaking energy and the amount of control over it when he was using it?
Akeno placed a finger against her lips and thought for a moment before answering.
"Ara... if I had to explain it simply it's that demonic power does not just float around aimlessly inside the body. It gathers and flows through specific points. If it remains still, the leakage is limited, because each point only releases a very small amount on its own. For example, the power centered around the solar plexus mainly leaks from that area alone, so the overall loss is relatively small"
"But the moment you actually use that power, it begins moving through the body. It spreads toward the shoulders, the arms, the hands, the legs, and the feet depending on the technique. That means the power is no longer concentrated in one place. It is passing through many points at once, and the more points involved, the greater the total leakage becomes."
She paused for a second and anticipated Issei's next question, "And yes, the amount of power inside a point does affect how much leaks out... but only to a certain extent. Studies gathered over thousands of years showed that even when a point holds more power, the increase in leakage is only slightly higher, not drastically so. That means quantity alone is not what makes the difference."
Issei looked completely lost, the amount of shit that entered his head was making it fume. Akeno and and Seekvaira noticed his expression and smiled, "You can just think of it as, 'energy leaks from the points of the body, and when you're using techniques you use more points so you leak more.' Adrien's energy points just don't leak at all." Seekvaira said.
"OHHHHH!!!! Now I get it, wait isn't that too overpowered? What the hell! When I use 100 mana points to use a technique, he uses 10. That's cheating!". Issei understood it in his own gaming sort of way.
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Yeah this was a chapter with a lot of info, but I want to start explaining slowly how Adrien's powers will work since I don't plan on giving him free power ups from systems and Gacha.
I put this simple power system as a base, this is not canon at all by the way. It's just that I don't like powers that doesn't show how and why it works. I will go in more details in the next chapter on how power (Demonic, Holy, etc..) will work in this fan fic.
The Idea might be flawed from somewhere so if yall think that it's not really well made or has a plot hole somewhere please give me your opinions