Having completed my filial duty of washing the dishes, I dashed upstairs to my sister's room like the wind.

A knock on the door cut through the silence of the hallway.

"Come in," my sister's voice came from inside.

I opened the door as calmly as possible, trying to steady my hands, which were trembling with anticipation.

My sister's room was quite spacious, like every other room in our house. One quick glance was all it took to tell that the person living here had an impeccable sense of order. Everything was in its place with precision and care, as if it were a display in a showroom. There wasn't a single item on the floor, not a speck of dust in sight.

The bookshelf along one of the walls was particularly noteworthy. It was filled with books of various genres and topics, each standing perfectly upright like soldiers at attention. Thick volumes of classic literature stood alongside modern bestsellers and scientific works. It was a clear reflection of Tomoe's love for reading and the breadth of her interests and knowledge. The shelf also had a few neatly arranged souvenirs and framed photographs, each seeming to hold its own special significance.

On her desk, positioned near the window, lay perfectly arranged study materials and stationery. The desk lamp was angled to illuminate the workspace in the most efficient way possible.

"Your room's spotless," I commented, sitting on the bed across from my sister.

"What, did you expect it to be different?" Tomoe's face twisted with mild annoyance.

"No, no," I laughed nervously, scratching the back of my head in embarrassment. "It's just… compared to my room, this is a perfectionist's paradise."

"I just don't like clutter," my sister smirked, clearly pleased with my explanation.

"Alright," I said, crossing my legs and slapping my knees to get her attention. "Where do we start?"

"How eager," Tomoe smiled knowingly before continuing. "Then again, I was the same when Mom first told me the truth about our origins."

"By the way, about that," I paused for a second, thinking. "Mom mentioned that since I'm not a witch, I don't meet the minimum requirements for training. What did she mean by that?"

"Hmm," Tomoe tilted her head slightly, deep in thought, looking surprisingly cute as she did so. "I think it's best if we start with the basics — what human magic is and how this world operates. But I'll only give you a broad overview, since you'll get more detailed information from the textbooks I'll lend you."

"Good, that's even better," I leaned forward, excitement bubbling up inside me.

"If I didn't know you better, I'd say that sounded a bit disrespectful," Tomoe smirked slyly.

"I didn't mean anything by it!" I protested, waving my hands.

"Don't worry, I know," she said, shaking her head, a soft smile creeping onto her face, her eyes warm with affection. "But I do like seeing this side of you. The way you get excited and forget to filter your words… You're really acting like a kid right now."

In response, I could only curl up in embarrassment, awkwardly scratching my cheek. Even in my past life, back when I was a student, I'd sometimes get overly sincere and childlike when doing or learning something genuinely interesting. I guess that's why I was good at what I did.

Tomoe watched me as I mulled over her words and smiled. Then, taking on a more serious expression, she nodded like a teacher about to give a lecture.

"Let's start with what you already know: the human world," she began. "At first glance, it's the same Earth we're familiar with — where the Sun shines by day and the Moon lights the night. But humans, going about their daily lives, are unaware of the supernatural beings and magic hidden from their ordinary view. In the shadows of our 'normal' world exist secret societies, organizations, and supernatural species like vampires and yokai, known only to a select few."

She paused to let that sink in before continuing.

"Next, as a mage, you need to know about the 'Three Factions,' which include devils, angels, and fallen angels. Let's start with the Underworld, also known as Hell. It's a separate dimension divided between devils and fallen angels. Human mages have the most contact with devils and fallen angels. The Underworld is roughly the same size as the human world, but it lacks oceans and seas, so there's much more available land." Tomoe paused for a moment, searching for the right words. "Interesting fact — the flow of time in the Underworld used to be different from the human world, but for the sake of reincarnated devils, it was synchronized with ours."

Stolen from its rightful author, this tale is not meant to be on Amazon; report any sightings.

"Reincarnated devils?" I raised an eyebrow, sensing something off about that.

"After several back-to-back wars involving devils, their population dwindled significantly. Devils aren't very fertile, largely because of their near-immortality. But they're clever, so eventually, they created a special system that allows other races to become devils. And yes, humans are the ones most frequently reincarnated as devils," she added, noticing the spark of interest in my eyes. "Some by choice, others through trickery, but the fact remains — there are so many reincarnated humans that they even created a moon and, as a result, night in the Underworld for their benefit."

"And people just give up their humanity that easily?" I asked, astonished.

But the more I thought about it, the quicker I realized how foolish my question was. Giving up one's humanity is probably the least someone would be willing to do in exchange for power. Besides, there are people who, while technically still "human," become such monsters and scumbags in their lifetime that reincarnation as a devil would probably feel like earning a "noble title" for them.

"You've already figured it out, haven't you?" my sister smiled knowingly, clearly guessing what was going through my mind. "Still, reincarnating as a devil has its perks. Immortality, strength, political influence of the house you have joined. Compared to all that, human pride doesn't count for much. However, there are downsides too — becoming a devil means you're permanently Heaven's sworn enemy. Heaven refers both to the faction of angels under God's leadership and their actual dwelling place. Its exact size is unknown, as it's vast, but we know it's structured into seven levels. Angels serve as the army of the Biblical God and are on par with both fallen angels and devils."

"And now, let's talk more about devils, angels, and the fallen," Tomoe continued, quickly shifting the topic. "Devils are the rulers of the Underworld. They wield immense power and can manipulate magic at an incredibly high level. The devils are ruled by 'Four Great Satans' and a 'Great King,' who leads the devil council. Their political system resembles an aristocracy, with noble houses and commoners. Originally, there were seventy-two Pure-Blooded Devils clans, but more than half are now extinct, with only thirty-two officially recognized."

"Next are the fallen angels — angels who were cast out of Heaven for their sins. They live in the Underworld as well, and they're the smallest group among the 'Three Factions.' The fallen angels call their faction 'Grigori,' and it's led by a governor, a vice-governor, and several high-ranking leaders."

"And finally, the angels — the natural enemies of both fallen angels and devils, due to their power of light, which is lethal to any 'evil' being. At the top of Heaven sits God, followed by the 'Four Great Seraphim,' the most powerful of the angels. Besides them, there are ten more seraphim, all loyal to their lord."

Tomoe delivered all of this in one breath, barely pausing. Even after she stopped, her words echoed endlessly in my mind.

What kind of madhouse have I landed in? Seventy-two devil clans — Solomon's ass, what!? Fallen angels, angels, the actual Biblical God!? And amidst all this insanity, humans are still just walking around like it's no big deal? What is even happening in this world!?

I hadn't cursed this fiercely — or this much — since that time I accidentally crashed a server during my internship.

"How are humans not dead yet?" I couldn't help but blurt out, staring at my sister.

Tomoe glanced at me and burst out laughing.

"Oh, I haven't even told you about the other gods and their factions yet."

"Other... Gods?" I exhaled in shock.

"Yup."

"Allah?"

"Nope," Tomoe shook her head.

"Indian Gods?"

"Bingo!"

"Odin?"

"Yup."

"Greek Gods?"

"Yup."

"Celtic?"

"Yup, yup."

"Japanese?" I threw this one out there after a moment of thought.

"That too," my sister nodded affirmatively.

"Jesus—"

"He's gone by now."

"—Fucking Christ" I couldn't hold back a curse.

"Hey! Watch your language," Tomoe scolded, frowning. "Besides, it's not all bad. Many Gods actually love humans and see them as the 'children' of this world. And angels, too, protect humanity, since, for Heaven, people are God's creation. That said, even with this divine protection, humans still face their own challenges. Which brings me to the topic of magic and the 'Sacred Gear'."

"Sacred Gear?" My ears perked up at the unfamiliar term.

"I won't go into too much detail today, but here's the gist: Sacred Gears are weapons bestowed upon humans by the Biblical God Himself. They're also known as 'God's Artifacts '. Sacred Gears are something only humans can possess. They're born with them, and eventually, usually under stress or strong emotions, their powers awaken," Tomoe explained, tapping her chin thoughtfully. "It's thanks to these Sacred Gears that humans can stand toe-to-toe with other supernatural beings… which, to be honest, is a little unsettling, because human magic is still weaker than demonic or divine power."

It was hard to miss the bitterness in Tomoe's expression. And after hearing about the Sacred Gears, I couldn't help but feel a tinge of that bitterness myself. In the end, humans only become truly powerful because of these 'God's Artifacts.' Those who don't possess them have to rely on magic, but even that doesn't grant them the same level of power as the weakest of the Longinus — the group of the most powerful Sacred Gears.

That's why, when my sister told me about a man named Vasco Strada, I immediately gained a deep respect for him. A man who became as strong as a God without any divine aid, relying only on his own human potential — that's someone truly extraordinary.

Vasco Strada… I'll remember that name. I've always admired exceptional people, and hearing about someone like him, I instantly made him a sort of "goal" to strive toward.