Why the Heck was I Reincarnated in DxD without a Cheat Power!? (High School DxD SI Chapter 3)

"So add the thermodynamic equation here, the kinetic energy at this part, and the...wind speed here?" Atsuko asked Akeno with a tired voice, dark circles under her eyes.

The magic student and teacher were looking over a large sheet of paper, like those used by construction engineers, art students, and lazy students making school presentations.

A large circle was drawn on it, with a smaller circle in the middle. The middle circle had a simplified drawing of the sun, while the outer circle had equations written along the edges of it.

The sun in the middle of the drawing is meant to be a symbol Atsuko chose to represent herself, as a way to easily connect to her magical energy to the spell formula. The equations were instructions for what she wanted her magical energy to do.

This was how Magic in general worked.

"Yep, all looks good." Akeno said with a smile. "You now finally..." she paused for dramatic effect. "Have a basic fireball spell."

"Yes, I know. All this work and it's something basic. You don't need to remind me." Atsuko whined.

For a week now, Atsuko had been learning magic from Akeno. This was their new contract was one of student and teacher. Atsuko would learn magic from Akeno, and in turn Akeno would use Atsuko for personal errands, as long as they didn't exceed Kuoh City's range, and do not hold any life threating situations, such as combat.

For the most part Akeno had Atusko doing grocery shopping for her, or sending messages to people around town, or Sona's Peerage. There had been some teasing here and there about trying out sex toys or bondage outfits on Atsuko, but neither acted on it, as Atsuko didn't seem scared of Akeno's 'innocent' insinuations.

"Yes well, normally, new students are able to at least write up the formula for a basic fire spell within a day of getting a feel of their mana and learning how magic worked." Akeno said lightly. "Unless you've been...distracted in our session. Oh dear, could this be my fault~?" Akeno held a hand to her cheek, giving a teasing laugh.

"Nah, it's because of this!" Atsuko folded the fire spell sheet, and took out another one from her bag, and unfolded it. "Ta-da!"

"This is..." Akeno looked on with wide eyes at the much more filled out magic circle with nearly a hundred of equations written in small handwriting, divided by sections, each one handling an aspect of the spell, that is then continued by the next section, and the next and the next, till it wraps around full circle for the singular effect of the spell. "This is the Intimacy Spell I showed you on our first day?"

Atsuko originally requested magic lessons to learn Transformation Magic, to learn how to give herself a futa cock. Akeno agreed, and showed Atsuko a spell that can simulate one's nerve to quickly make them orgasm as motivation.

Akeno had, of course, been cheating with Devil Magic, she hadn't expected Atsuko to actually make a human version of the spell.

"Just call them Sex Spells, or Bedroom Spells if you wanna be coy." Atsuko rolled her eyes, to which Akeno huffed in amusement before focusing once more on the magic formula.

"I don't know the specifics. I do know that part is a chemical reaction," Akeno pointed at a section in the drawing. "This one is for electric discharges, and this one..." she knitted her brow at another section. "Hormonal imbalances? I'm not actually sure. I would need to show this to an expert to check, but I'm pretty sure most of these," the equations, "comes from college level courses." Akeno turned to Atsuko, the question was obvious.

"I asked Dad to buy me a few dozen books on anatomy and biology, saying I'm interested in medical diagnostics for when I go to university. He obliged."

"You've been reading college textbooks, this past week?" Akeno asked in wonderment. "Is that why you looked dead on your feet, all the time now."

"Yea-" Atsuko yawned unable to stop herself. "Yeah. Really wanted to get this done. I mean elemental magic is cool and all, but I wanna make people cum with a touch." She said with a wide grin.

"Fufufuf, very well then. I will have to check this with one of Rias's tutors just to be sure nothing is amiss, but..." Akeno smiled at her student, and said conspiratorially. "Wanna Summarize the spell and give it a test run?"

Summarize in magic terms is when the Magician writes their spell, replacing the equations with symbols, each symbol representing an equation, or a section of equations. The user would know what each symbol mean and represent, as it was for their own ease of use. It's why magic circles tended to be personalized, with each magic user's magic circle having its own unique look.

Of course, there was also a standardized form to magic symbols, that is used by magic institutions. Each organization having their own symbols to represent equations, in order for them to have collaborative spell work.

"Hell yeah!" Atsuko pumped her fist in the air, pulling up energy from within her, excitement making her more awake. "...But we don't exactly have a test subject?"

"That's easily fixed." Akeno smiled, then pointed at the floor. "Kai," she called out.

A small magic circle appeared on the ground after a moment, and a small hand-sized Oni appeared out of it.

"Guo," it let out a sound.

"Ooookay, what's that?"

"My familiar. They're considered a milestone for a Devil or a Magician to gain one. We'll get to them in our lessons eventually." Akeno replied, before turning to the tiny oni. "Find me a rodent or critter and bring it here. Not one from the school labs or kindergarten."

"Guuuo!" It saluted and vanished in another magic circle.

Some minutes later Kai returned through the magic circle holding a struggling rat, that couldn't get out of the oni's grip no matter what it did.

Akeno pointed a finger, easily paralyzing and floating the rat out of her familiar's hold.

"Thank you, Kai." The familiar gave a nod and dismissed itself.

Akeno placed the stilled rat on the table, next to the sheet of paper. Atsuko finished up writing the magic formula on a fresh sheet of paper, this one Summarized with her symbols on it. She looked at it a few times to memorize it once more, before turning it over on it's back. Atsuko closed her eyes and ran the spell in her mind a few times.

Yes, she could just place the rat on the paper and run her mana through the paper to activate the spell, but as Akeno told her, it was important for a mage to learn how to use their spell without needing an aid. Thus memorization.

"Okay, I'm ready." Atsuko opened her eyes and nodded to her teacher.

Here goes. Atsuko took a breath and called on her mana.

Magical energy tended to just react according to its environment. If there was water, it purified it. If there was fire, it intensified it. And so on and so forth.

It wasn't incorrect to say that magical energy just made things more of what they are, but rather it allowed things to manifest according to the will attached to it. It's why some people, like monks, say everything has a soul or will. A mountain becoming a home for godly being and a sacred place due to the accumulated mana there is a good example of the effect magic had on the environment.

That's were magic formulas came in. It took the magic energy and funneled it through reason and logic of human thought and understanding, so that the mana would act in the desired manner and bring the wanted result of the magic practitioner.

An ethereal glowing circle appeared under the rat, rotating slowly. It's light shining from it engulfed the rat for a few seconds then disappeared.

For a while nothing happened. The mage student and teacher leaned forward to get a closer look.

The rat opened it's mouth, like it was trying to scream, but not knowing how, as it vibrated. Specifically it's hips.

"Wait, is it..." Atsuko wondered if she succeeded.

Then the rat thrusted it's hips down, like it was pounding into a mate, letting out squeaks that made it obvious what was happening. If the liquid under it's leg wasn't already a clue, and now that the girls looked, they noticed the rodent's testicles were enlarged.

"Wow. I'm actually impressed. You made such a complicated spell and got it working on the first try." Akeno said, actually sounding proud of her student.

"Woooah! Boo-yah. One step closer to being a Sex Goddess." Atsuko pumped her fist in the air, then started hip thrusting as a dance of victory.

"Well, you're not supposed to have the sensitivity so high, as to make the target climax from the air around them. A+ for effort thoug-"

"Sqee, sqee, sqee, sqee, sqee, sqee, sqee!" The rat's hip-thrusting increased in speed.

"Uuummm, is it suppose to do that?" Atsuko asked worryingly.

"Pretty sure-" Akeno said slowly as she raised an eyebrow at the animal's behavior.

Then both girls noticed how enlarged the rat's balls were, as to be the size of its head.

"Cancel! Cancel!" Atsuko stopped powering the spell.

It was too late.

"Sqeeeeeeeeeeee-" The rat gave a shriek of pleasure and pain, as its balls exploded, popping like a blood zit.

"OH MY GOD!" Atsuko jumped back screaming.

Akeno just looked at the poor animal with wide-eyes. She had flinched at Atsuko's exclamation, but even she didn't mind it at that moment, as it was warranted.

"...Well, I take back what I said." The Gremory Queen went and forced the rat to sleep, casing a healing spell on it. Sure, killing it would be the easy, and maybe, right solution. But after what it endured, Akeno felt it deserved a second chance at life. "If I was a school teacher, I would fail you on this project."

"Fuck me, I would give me an 'F'." Atsuko agreed.

The two stood in silence for a moment, only the sounds of the rat's breathing was heard. It almost sounded like it was feeling pleasant now that it's balls regenerated.

"So, what do you think went wrong?" Akeno said as she finished healing the rodent, and gave it to her familiar to throw it out into the wild.

"I'm guessing because I set the measurements for a human body, rather than a rat's." Atsuko gave a thoughtful frown, while rubbing her head.

"That is very likely. I suppose we'll never find out. Almost a shame I'll have to send it for verification, rather than we try it out on our own for a while." Akeno said with a sadistic smirk.

"Oi, oi, oi, choutto a minute. That's yari sugi-ing it. Don't you kangaeru-think?" Atsuko said, causing Akeno's eye to twitch at that butcherizing of language.

Ever since Atsuko learned how the Devil trait of Language worked, she would at times use two different languages at the same time just to mess with Rias or other devils. It caused the devil to hear an irritating echo like a word being said twice over, while being accompanied by an echo-y nail on board scratch.

"You know what, I think it's time for a physical lesson?" Akeno's hand started to have electric sparks go around it.

"Eh, what does that have to do with magic?" Atsuko said walking slowly back toward the classroom door.

"Don't you know, it's important for a mage to be physically active, so they can move and cast at the same time?" Akeno grinned.

"Onigai-please, Akeno-senpai! I'm truly gomena-sorry!" Atsuko was almost at the door, and her act fail. She couldn't keep her smirk off her face, even as she bit her lips, to stop laughing at her senior's annoyance.

"Run." Akeno growled.

=====

Issei sighed as he was looking out the window of the ORC building, from the office he was in. He paused working in organizing the papers related to the contracts Rias and her Peerage had completed, a feeling of baseless anxiety in his stomach.

"Everything alright, Issei?" Rias asked, noticing her Pawn's melancholic demeanor.

"Ah," Issei blinked, before smiling sheepishly and rubbing the back of his head. "Sorry, I started thinking about Atsuko, and started feeling worried."

"I see." Rias smiled, while Atsuko's true self was...a shock, she thought the bond between the siblings was actually pretty sweet. Actually, observing Atsuko from a distance, she did find her pretty amusing. Maybe it was just the first impression that overwhelmed her? "You know, I actually do plan to invite her to Peerage as my Bishop."

"Eh?" Issei looked back in surprise. "Wait, really?"

"Well, yes. A potential of a Pawn and a half may not seem like much, but Atsuko is pretty hard-working, and Akeno had been saying good things about her for the past week." Rias nodded.

Atsuko's persona at school was once of a diligent student, who was hardworking without showing the exhaustion of that hard work. She would sit in every club, and practice till she was the best in it, without joining. She would act as a substitute for those clubs as needed, being a sort of legendary figure that would be the ace of any club, without being held down to any one of them.

"I thought you couldn't use the Piece on her, because her potential wasn't three Pawns?" Issei asked.

"No," Rias shook her head. "If someone's potential exceeded a Piece's value, I can't reincarnate them using that Piece. But if their potential is less or equal to the Piece, I can use it on them without any issues."

"Ah, okay then." Issei nodded. "But why didn't you do that before?" He tilted his head in a way that Rias found to be so cute.

"Well," Rias smiled mischievously a bit. "I guess I wanted to prank Atsuko, by making her jealous of her brother for a bit." She giggled in a way, that had her breasts vibrate heavenly, and cause Issei to focus on them. Not that there isn't a time, where he doesn't take the chance to focus on them. "Please don't tell her. I promise to recuirt her soon, but I wanted to tease her for a while longer." Rias said with a shushing gesture, and winked at Issei.

"Haha, yeah okay, I'm in." Issei blushed and laughed back. "But please don't wait long. When she started doing all-nighters again and downing caffeine shots, this time to learn magic, I was beginning to get really worried."

Rias blinked at that. "Surely it's not that bad."

Issei met his King's eyes and gave her a hard stare. "If there's one thing I've learned in this life, it's that Atsuko can't be left unsupervised for long periods of time."

Rias felt herself shiver at the statement, but forced herself to push that feeling down.

"Surely, it can't be that bad." She said with a jovial tone. "What's the worse that can happen?"

=====

A few days later, Atsuko was walking home at night, she met a white-haired priest oppose to her on the street.

"Well, well, well," His slimey voice causing Atsuko to pause and look at him. "I smell a devil on you, bitch. Must be my lucky night!" Father Freed Sellzen cried out in joy, as he lit his Light Sword up. "First day here, and I get to give a whore a chance to repent and scream for the Lord! Not that he'll hear you. Keehahahahaha!"

Atsuko flinched, and hid her lips almost twitching into a smile behind her hands. She took a sleeping pill from her pocket, and hid it between her teeth and cheek.

"PLEASE, DON'T RAPE ME!" She cried out, bowing her head and putting her arms up in an 'X', in a hopless effort to defend herself.

"...Well, I wasn't going to before."

=====

Ring! Ring!

"Hello?" Rias answered the club's phone. Only people that knew she and her club members were devils would call her at this hour. "Rias Gremory, how can I help you?"

"Hey~, Rias-senpai?" Came the cheery voice of Issei's sister.

"Atsuko, how have you been?" Rias leaned back in her chair and smiled. She wondered if the girl will try to cutely beg to be part of her Peerage, but that few weeks of Issei bragging how life as a Devil. "Do you need anything?"

"Yeeeeah... Did you know that you have a Fallen infestation in your town?"

"What?" Rias sat up, now very focused due to this serious issue. Her tone alerted the club members that something was off, and had Issei asking if something was wrong.

"Yeah, found out from this guy, Freed Sellzen, and thought I should tell you."

"What? Sellzen!? Atsuko, that man is insane and dangerous, you need to run and summon me right now!" Rias stood up.

"Yeah, I don't think he's gonna go anywhere right now." Atsuko's tone held a note of amusement in it, that angered Rias.

"Atsuko, this isn't the time to joke around. Freed is-"

"Say, Rias, how do I get rid of a body?"

Atsuko's question cut off Rias's rant.

"...What?"

"Yeah, I think I may have fucked him to death."

"..."

"Sooo, as a Devil, you have any tips?"

"You what?"