The Protagonist's Sister Is Actually The Strongest

“A-Anna!”

Song screamed as the hole sealed shut. The power of Bestia as a World remained immense—it could repair these spatial cracks, provided no otherworldly force kept prying them open.

“Song!”

His mother rushed to him and pulled him into a tight embrace. The boy felt a rush of gratitude and relief that she was alive after everything. His recklessness had nearly killed them both.

“I’m sorry…! I-I didn’t know I had so much power. I couldn’t… I couldn’t control it…! And…”

“I know! That was incredibly reckless, but… I’m so glad you’re back!”

“Anna’s clone sent me back, but… she stayed behind, and I don’t know if she’s okay!”

“I’m fine…”

Necro appeared behind the Heavenly Empress, groaning softly as she pressed a hand to her forehead.

“That thing directly probed my soul, though. But it seems… it was utterly shocked by what it discovered and tried to assimilate me.”

“A-Assimilate?” Song asked.

“What do you mean, Anna?” the Heavenly Empress asked.

“Void Rulers devour Stories. When it tried to consume mine… well, it couldn’t stomach it,” Necro explained. “All of us are currently developing them—our Stories. They hold real power in the universe; they leave a mark, proof of our existence. As we live our Stories, progress, face challenges, and overcome them, the Stories grow stronger. We can cultivate Dao Trees within our Souls, and through them, powerful Traits that elevate our beings while generating cosmic energy.”

“T-That’s so…” Song trailed off, still dazed—that was an overwhelming amount of information delivered all at once.

“There are countless more layers to ascending from mortal to Constellation, but that’s the core of it,” Necro said.

“Then that thing tried to eat your Story?” the Heavenly Empress asked. “But you’re not stronger than it—how did you…?”

“I have no idea… but it might be because of what I told you—that this world… I had read it as a novel,” Anna explained. “I don’t fully understand it myself, but somehow that novel is part of my Story, and… since the novel encompasses this world, trying to devour it is like trying to devour all of Reality… impossible.”

“S-So you’re immune to Void Rulers?! That’s incredible!” Song exclaimed, eyes wide with shock and awe.

“N-No! I’m not completely immune—only if they attempt to predate my Story…” Necro sighed. “But if they simply crush me to death and shatter my soul, nothing will protect me.”

“I see… Even so, immunity to one of their most powerful attacks is a significant advantage you could use as a trump card…” the Heavenly Empress said. “However, against that thing, it may no longer work now that it knows what you can trigger in it… Was it damaged?”

“Severely… It screamed in such agony—it shook my very soul…” Necro replied. “But that only enraged it further. It’ll probably try to—”

RUMBLE!

Crack, crack…!

CRASH!

Suddenly, as Necro began to explain further, the cracks in Bestia’s sky widened even more. They spread rapidly as gigantic mechanical tentacles with enormous metallic pincers forced their way through, prying the rifts open.

This content has been misappropriated from Royal Road; report any instances of this story if found elsewhere.

“Yeah, that…” Necro muttered. “We have to regroup with everyone else—let’s hurry! The Heavenly Demon is still fighting the Demonic Throne Avatar. We need to help him!”

“Is it strong?” Song asked. “But Papa can handle it, right?”

“It’s far stronger than Beelzebub or that Spherical Demon Mammon used!” Necro gritted her teeth. “Let’s hurry! Quickly! That thing is… it’s the Avatar of that bastard!”

“That… bastard?” Song asked.

“The strongest Demonic Throne… Someone so powerful he even keeps other Constellations as pets!” Necro said. “Hurry!”

As they soared through the skies at top speed, the Heavenly Demon’s crimson eyes glared upward. The cracks continued to spread relentlessly across the heavens.

“This damned world is doomed…! Fucking hell!”

As he cursed, blood trickled from a small wound on his forehead, briefly blinding his left eye. He wiped it away with a swift motion, flicking the crimson droplets aside.

His entire body was battered—covered in bruises and blood. His black feathers had been torn apart in multiple places; even his sharp black beak bore several cracks.

His left wing hung shredded. He looked visibly exhausted—just as he had when he fought that Constellation alone.

“What’s wrong? Are you done fighting? It seems you’ve already given up… Should I kill you quickly, then? Ah, but it would be such a pity… Your feathers—I love them. Would you like to become my pet instead? I don’t have a bird in my collection yet.”

“…”

The Heavenly Demon glared at the source of the voice. A cocky, red-skinned demon sat cross-legged above him, several hundred meters away.

Its fiery red skin was covered in golden tattoos. Three black horns sprouted from its head. Long silvery-white hair flowed freely. Four pairs of black demonic wings extended from its back, along with a long tail ending in a sharp, stinger-like tip.

The demon appeared slender yet leanly muscled, with two pairs of arms tipped in sharp black claws. Eyes stared from the palms of its hands, and another eye gleamed on its bare chest.

Clad only in white baggy pants that covered its waist and legs, the handsome demon—with golden eyes and a flawless face—smiled at the Heavenly Demon.

“What’s wrong? You’re not speaking anymore? After bragging about being the strongest… I’m honestly quite disappointed!”

“Heh, you haven’t even seen half of what I can do, you delicate-looking bastard.”

“Hoh? Then go ahead! I’m waiting for your ‘full power’ or whatever! Hahaha!”

The demon laughed, spreading its four arms in provocation.

Around them lay hundreds of demon corpses. Just minutes earlier, five thousand had been present. The Heavenly Demon had slaughtered over ninety percent of them.

And the demon he now faced had simply watched the massacre—clapping and nodding in amusement.

When it asked the Heavenly Demon to become its “pet”—and was met with a punch to the face—their brutal battle had begun.

They had fought for barely a minute, and this was already the damage the Heavenly Demon had taken!

But perhaps that suited a masochistic bastard like him perfectly.

“{Seven Demonic Cursed Seals}: {Full Release}!”

RUMBLE!

“Hm?!”

The demon’s eyes widened as a tremendous surge of evil power erupted from the Heavenly Demon. Despite his earlier transformation, the darkness within him had never truly left.

If anything, both aspects now coexisted, their powers complementing one another!

After all, no matter what he had become, he would never abandon who he truly was—or the path he had walked until now.

All seven seals activated. The Heavenly Demon tore off his clothes, revealing his muscular, feathered chest covered in glowing cursed seals at full power.

Each seal released a different-colored mystical flame of evil energy—a potent negative emotion he had infused into his very body.

These evil flames, composed of Demonic Ki, converged into his chest, forming a core of profound darkness.

His body suddenly expanded threefold, becoming more muscular than ever. His wounds scarred over. His missing wing reformed from pure Ki.

“How amusing! You’re not a demon like me, and yet your power… It’s so similar to ours—I’m simply at a loss for words! Now I definitely want you in my pet collection, hahahaha!”

The demon ceased sitting cross-legged and laughed.

RUMBLE!

In a split second, the Heavenly Demon appeared above him. The demon’s eyes—all of them—widened.

BAAAMMM!!!

“UGH?!”

Its nose shattered as the Heavenly Demon’s fist struck with concentrated force. The demon’s head twisted violently, nearly snapping his neck as he was hurled downward with overwhelming power. Teeth scattered into the sky.

SPLAAASH!

He crashed into the ocean, sending massive waves surging. A gigantic, turbulent whirlpool formed as a nuclear-like explosion detonated immediately after.

BOOOMMM!!!

The punch carried the Heavenly Demon’s spiritual force, igniting a colossal blast upon impact.

“This is a new technique of mine—did you like it?” the Heavenly Demon asked, smiling proudly.

“I call it {Cursed Fist Explosion}!”

As he laughed, the seas trembled and turned pitch black. From the dark depths, a huge crimson eye opened and glared up at him.

RUMBLE!

The waters swirled violently, rising into the sky. The demon emerged atop the waves, sitting casually despite his swollen, bleeding face and broken nose.

“Hahaha! Amazing! Show me more! I like my pets as fierce as possible!”

“You really don’t understand, huh? I’m not going to become your pet, shithead!”

CLAAASH!

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