The Protagonist's Sister Is Actually The Strongest

It took him a few minutes to accept that I had to leave in 24… or maybe 23 hours now, but Song eventually felt better, and we were able to enjoy our breakfast. Zero One was supposed to be here too, but she had disappeared!

“Where is she now?” I wondered.

“She went outside my Realm…” sighed the Heavenly Empress. “I can’t force her to stay either. But from what I sensed with my Aura, she went to the Mechanical Root City, as we’ll call it for now. She wanted to do something urgent… for you, I think.”

“Ah, the… the souvenir or something,” I sighed. “I don’t know what she’s planning, but I don’t think I can bring stuff from this world back to mine so freely… If she gives me something too big or powerful, I’m sure they won’t let me… Or will they?”

I’d never considered the limits of what I could bring back home. What if I took a fragment of this Inner Realm or fused it with my Purgatory Realm? Could I then bring anyone inside it along with me?

Ah, well, it’s not like I’d ever try such a thing. That would be incredibly selfish. What kind of person could ask for so much from those who’ve already given them everything?

It would be beyond shameless!

“Anna, before you leave, I was thinking of giving you a fragment of my Inner Realm.”

Yeah, it would be utterly shameless to even ask for such a—

“EH?!”

“That sounds great!” Song said with a nod. “Maybe that way she can carry a bit of our world with her everywhere…”

“Yes… It’s an experiment, though,” Mom said. “I know you have your own Inner Realm too, right? Where you keep the Demons.”

“T-That’s the Purgatory Realm. It was created specifically to seal demons inside, but… yes, it has a vast space, and it can absorb… things. I haven’t used it much, but I absorbed a huge golden temple from a Murim Dungeon. There’s lots of Ki there. Also, there are two Heaven Fragments I never returned, which have been fusing with the Realm,” I explained. “I… uh, I think you could enter? Have I ever tried letting others inside? The Demons are connected to it—their souls, everything. Even if they die outside, they can slowly recover inside.”

“So that makes them immortal?! That’s pretty neat!” Song said. “Also, I remember you… you befriended the Demon King who stole my body, right?”

“O-Oh… I thought he was very strong, and he helped a lot… I called him Nemesis,” I muttered. “I’m so sorry, Song! I should’ve asked you first, but…”

“No, it’s fine,” Song said. “You can keep him… He’s also a part of me in a way! So, as long as he comes with you, it’ll be like I’m going with you too, right?”

“I don’t know if that’s the case… but that’s an interesting way to think about it,” I nodded. “Do you want to talk with him? He can’t talk, though; he only screams, but…”

“I kind of want to, yeah… If he’s leaving with you…” Song muttered.

“A-Are you sure about this, my son?” his mother asked. “That monster isn’t you, you know. You’re…”

“I know you’ve gone through a lot, Mom, since that happened to me,” he sighed. “But now that I’m finally myself again—and perhaps even stronger, as I fused with my Records—I think it’s fine. It’s time to confront him. I don’t want to kill him or anything. If he can be useful to Anna, that’s for the better, I think.”

“But Song…” she murmured.

“I think… in the time I spent with him all those years, I understood a bit of what Demon Kings truly are…” Song said softly.

“What?” I asked. “Y-You understood?”

That wasn’t something addressed in the original novel at all.

Demon Kings were nothing but super bosses my brother had to tackle—powerful challenges to raise the stakes of the story.

They were never developed beyond existing as seeds given to certain people with specific desires, talents, or potential.

But… what they truly were? That was never explored.

“Yeah… he might’ve been terrifying back then when you helped me escape my own body and fused my soul with my Records, helping me revive,” he said. “And I’ll always be grateful for that, but… although he was obsessive and slowly trying to merge with my soul, through that process, I understood what he was. The Demon King… or all of them, they’re… accumulations of an entire world’s… suffering.”

“Suffering?” I asked. “W-Wait, what? What do you mean by that?”

“I don’t even know how it’s done—perhaps through some powerful Alchemy,” he explained. “But Constellations create Demon King Seeds by gathering the Suffering, Pain, Agony, and Cries of Billions of Souls from a Destroyed World. That Demon King was born from the original world of Zero One…”

“…”

I was left speechless.

Why does this make so much sense?!

Then the Demon King we faced back home, Heisenberg…

Was it also a seed created from the suffering of another world, given to him by Lucifer?

No, that one was particularly weaker too… Maybe the seed wasn’t complete, and it was “completed” with his own suffering and agony, turning him into something bizarre.

It also helped that I interrupted his evolution, so he couldn’t transform into a full Demon King, making the battle… barely doable.

“Song, you’re a genius!” I said with a smile. “That means we could find a way to reverse a Demon King seed using the powers I’ve learned here—the power of Hope and Love. I doubt I can do anything right now, but… eventually, we could even reverse that Demon King and turn him into… I don’t know, something purer?”

“Is that possible?!” my mother asked. “If that’s the case… maybe Song could become truly complete by regaining his original body!”

“I’ll have to study it for a while, though,” I said. “But that’s something Dad taught me. To reverse seals, we can do the same with a Demon King. If their existence is truly made by forging and synthesizing all those Emotional Energies and Souls… it should be possible, technically…”

“Interesting!” Song nodded. “I’d love to help, but… yeah, I guess I won’t.”

“You can help a little!” I said. “If you meet him, maybe I can gain more insights into the process.”

“Hmm, good idea then,” he nodded. “I think I’m done with breakfast. Should we go? Mom, are you really giving her a fragment?”

“Yeah, it’s already prepared,” she said. “I was thinking of giving you this area—the golden palace and the surrounding mountains, rivers, forest, and lakes.”

“T-That much?!” I gasped.

“Oh, dear, my Inner Realm has grown immensely through the battles before. As I grow, it expands,” she said. “I think giving you a larger fragment might destabilize your own, so that’s why I chose a small piece. I would’ve given you a whole continent otherwise.”

“Wow… O-Okay, thanks, Mom… I can’t really reject such an amazing offer, but I feel a bit bad…” I sighed. “Is this how spoiled children feel?”

“Hahaha, you’ve done so much! You deserve to be spoiled, my dear,” she smiled, caressing my head and rubbing her feathered face against my cheeks.

“Thanks, Mom…” I kissed her beak. “I love you, and I always will!”

“Heh… You’re so cute,” she smiled, squeezing my cheeks. “Especially your face! Unlike us birds, you humans sure are squeezy!”

“Yeah, let me squeeze her face too!” Song joined in.

“Ouch, augh! S-Shtop…!” I cried as the two began pulling my cheeks playfully.

After they finally let go, I hurriedly finished the delicious breakfast.

There was a wide assortment of Chinese food—not like an American breakfast, more like eating lunch…

But it was all really good: spring rolls, fried rice, meat dumplings, grilled fish, fried tofu with soup and noodles, and more.

Man, I ate until there wasn’t anything left on the table!

“You sure ate a lot! I didn’t know you could eat so much with that little tummy of yours, sister, heheh,” Song giggled.

“I… Burp… Ugh, I might’ve eaten too much, but I couldn’t let the food go to waste!” I said. “This’ll be my last meal from Mom, and she makes such delicious food! I couldn’t resist.”

“Aww… That flatters me so much,” she smiled. “I’m so happy I can finally cook for my children. I always dreamed of doing this back then—a dream I thought I’d never fulfill…”

“And even when I’m gone, Song will be here for you,” I said, holding her hand. “You’ll eat all your mom’s food, right?”

And he’ll even eat the meals he avoids all the time, too, right?

-----