We have been goinig at it for hours now and were beyond exhausted.
But we didn't stop.
Serafall was lying on her back and I was leaning towards her. Her face was nuzzled in my neck. She was softly moaning right on my ear as I lazily moved my hips and buried my big dick inside her swollen pussy.
We groaned and moaned as we reached another intense orgasm and completely collapsed , to tired to do anything else.
We both let out heavy breaths and rested in hopes of recovering soon.
After sometime I got up and helped Sera up aswell.
"We should hurry back Sera-chan. If we dissapear for any longer we can't make any proper excuses." I said to Sera.
"But my whole lower body is hurting and trembling. I can barely stand!!! It's all your falt hmph!!!" She pouted.
So cute!
After a short banter I helped Sera dress herself and we went out but not before sharing a lewd passionate french kiss.
'Congratulations you've earned a reward for conquering Serafall Leviathan.'
Ability:Fertility control.
What does it do?? Well the name is enough to understand.
----
It was strange.
Even though I'd been preparing for this moment for so long, when we stepped off the train and into Kuoh City—our new territory—it still felt surreal. The human world carried a stillness the Underworld never had. The sky here wasn't eternal twilight; it was blue, soft, and limitless.
The House of Gremory was the official devil authority over this region. So when we arrived, there were no border restrictions, no barriers, no ceremonies. It was ours by right.
And now, Kuoh Academy would become our new battlefield.
-----
Enrolling wasn't hard. Most of the paperwork had been handled in advance by Grayfia and Sona. The school accepted us as elite transfer students. Rias, of course, dazzled everyone on sight—her beauty and presence made the student body whisper like they'd just seen royalty. Which, technically, they had.
Sona Shitori—serious, brilliant, already in control—took over as Student Council President from day one. Her entire peerage slid seamlessly into the council roles, and no one dared question it.
Not because the faculty wanted it. But because Sona made them want it.
----
I was there when it happened. Late afternoon, the school still half-closed from break. Sona had called a "meeting" with the faculty board and senior administrators.
Tsubaki opened the doors. The rest of us remained hidden outside the hall, magically concealed, but I could still hear everything.
Sona's voice rang out, calm and poised.
"Let's speak honestly. This school is not safe. It's a territory of the devils. Rias Gremory and I are devils. We are here not to disrupt… but to guide."
A teacher objected. Another questioned their authority. That's when Sona dropped her trump card.
Hypnosis magic.
Subtle. Elegant. Deep. Sona and Tsubaki worked in tandem, supported by illusion magic to cloud memory and perception. Within ten minutes, every teacher, administrator, and board member in that room believed they had willingly appointed Sona as President and approved all staff changes.
Genius.
Sona wasn't doing this for power. Not like her sister, Serafall. This was her trial run. Her dream was a real school, one day, for low-class devils and hybrids. This? Kuoh? It was training.
And I respected her for it.
----
I sat by the window of the empty third-floor lounge, watching the school buzz as orientation week picked up.
This place… it was exactly like I imagined it.
The ridiculous elite politics of Shuchiin. The gambling dens behind classroom walls like in Hyakkou. And the silent, brutal systems of Advanced Nurturing High School: points, class ranks, exams with consequences.
It was absurd.
It was perfect.
Because this world—was my desire made manifest.
When I reincarnated, part of me longed for this. A stage where devils and humans danced in secrets. Where magic and manipulation walked beside algebra and student elections.
If we didn't abuse our demonic magic then even we devils will find this school challenging.
----
Rias had taken control of the Occult Research Club room. It served as our base of operations. Her peerage had settled into routines quickly—Kiba charming everyone, Akeno soft-smiling with hidden menace, Koneko trailing behind like a quiet ghost.
And me?
I watched. Learned.
Rias had begun organizing human contracts—the cornerstone of devil livelihoods. Every human had mana, no matter how little. And by forming pacts, we could grow stronger, and build networks of influence.
But unlike most devils, we didn't do it for status.
We did it also for money.
Rias's father still held the purse strings. Her independence was a façade. If she wanted her peerage to live freely, to train and move and act without her family's approval, she needed capital. Real capital.
And she was willing to work for it.
----
By the second week, the club had set up magical arrays to detect potential clients—humans subconsciously seeking help, hope, or escape. We started receiving requests.
A girl wanted revenge on her cheating boyfriend.
A boy wanted to win the student elections at any cost.
A teacher wanted to restore his youth.
Small wishes. But enough to spark contracts.
We rotated duties, and I took on my first job with Koneko—tracking a gambler in the lower school who owed debts to a shadow group rumored to be mana harvesters.
Turns out, they were just normal humans.
But the tension reminded me: This world may have started as fiction to me—but it was real now.
And dangerous.
The Shadow System of Kuoh
Classes here weren't normal.
Every class had "hidden exams"—evaluated not just by tests but behavior, influence, leadership. Every student had points, and they were traded like currency.
I learned fast: The children here weren't ordinary.
Some were heirs of wealthy tycoons and powerful politicians. Some were elite scholarship winners with IQs off the charts. Others were just ruthless social manipulators.
The gambling dens—hidden behind gym walls and abandoned classrooms—were terrifyingly organized. Chips represented points. Points represented power. If you fell into debt, you risked social exile—or worse.
If your points got into minus then you will become a house pet. Basically a slave.
If you can't pay back your debt to another person you will become that person's slave untill you pay back in full plus interest.
Untill then they are free to do anything with your life as they please.
It was exhilarating.
Akeno had already won two private games. She was a very sadistic girl. She was deriving pleasure from breaking a female students will. She had already made herself a slave.
Maybe I should start making personal slaves as well. I have even picked up few interesting targets.
We weren't just devils pretending to be students anymore.
We were students.
And this world wasn't a playground. It was a proving ground. Every move here mattered—academically, politically, magically.
-----
Venalena just left the clubroom. The room was still being illuminated by the teleportation magic she cast to go back to the underworld.
I had been frequently calling Grayfia, Venalena and Sera ,seperately ofcousre to have some fun. I didn't have the courage to face three Yanderes at the same time yet.
As I sat alone in the clubroom that evening, listening to the others talk in the hall, I smiled to myself.
"This… this is where it begins."
I checked the system timer.
It had been exactly one year since I created [Master of strings].
Which meant… the cooldown was up.
I could create a new skill.
I stared out at the setting sun as a system prompt slowly shimmered into view.
[Skill Creation Available]
Let the next act begin.
End of Chapter 19