The Protagonist’s Sister Is Actually The Strongest [An Action-Packed LitRPG Transmigration and Progression Fantasy]

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CLASH! CLASH! CLASH!

An intense battle between three powerhouses resonated across the Demonic Castle. Jack, Lee, and the Death Apostle Neberius had been in a tight lock between the three.

While Neberius continuously pursued either Jack or Lee as they attacked him, Lee was purposely hiding around and escaping the Demon while seeking the opportunity to strike Jack when he fought the crow-faced bastard.

This made for an increasingly complex and stressful battle, as Jack had to navigate against two incredibly strong and tricky foes at the same time. Neberius, no matter how much he was taken down, would always come back for more.

And Lee, with all his skills and tricks, was incredibly annoying, becoming more and more of a pain in the ass whenever he hid and appeared out of nowhere!

Although Jack had the power of shadows, even this seemed to be working against him!

“{Shadow Veil}!”

Jack hid within the shadows as he evaded the powerful kicking strikes of Neberius, which landed on the wooden floor and shattered it into countless pieces.

CRASH! CRASH! CRASH!

“CRAAAH! Where did he go?!”

Neberius swiftly moved his wings around, having regenerated them several times after they were cut down, and scanned his surroundings, finding shadows spreading around his entire body.

“{Shadow Domain: Wolf King’s Abyssal Jaws}!”

Jack went all out, unleashing all the shadows stored within his own shadows as they wrapped around the Death Apostle’s vessel and shapeshifted, transforming into gigantic wolf maws!

“Dammit! Again with this?!”

Neberius had been captured in the same trick two times already, but every time he ended up taking a lot of damage! He tried to fight back, kicking, punching, and using his feathers as hundreds of blades, cutting through the jaws.

However, they ultimately gathered around his body and started biting and tearing apart his body! In his rage and madness, the crow-like demon apostle channeled the strange aura that Jack noticed he had been using lately, his {Radiance}! Something that not even Jack knew about yet, even when he was the protagonist.

FLASH!

The shadows suddenly melted and dissipated as Jack gritted his teeth in frustration! He couldn’t even believe the bastard got away from his ultimate technique a third time now!

“CAAAH… Y-You’re sure something, human! To force me to use my {Radiance} yet again…” Sighed Neberius, his wounds began to naturally recover. “Thankfully, Beelzebub made sure to make very tough vessels for us! Kehehehe!”

“{Radiance}?! What the hell is he talking about?” Jack thought. “Oi, Fenrir! Do you know what a {Radiance} even is?!”

“I guess I never told you about that... You’re still too early to acquire one anyway. But they’re an expression of the soul! Once you grow strong enough, you’ll be able to acquire a Dao Root, and then grow Dao Branches that’ll evolve your {Radiance} based on the Traits you unlock.”

“What? English please?”

“Tch, it doesn’t matter now! Having me within your body and soul is already like having one yourself, although very weak! Also, watch out!”

“Ah!”

Jack quickly realized an enormous crimson snake surged from his back, opening its massive maws and attempting to engulf him completely.

Anna’s big brother gritted his teeth in frustration, his entire body already having transformed into his half-human, half-werewolf form, which granted enhanced Stats with less Mana Consumption.

“RAAAH!”

Wielding the other half of Gram he possessed, Jack mightily slashed the snake into halves, making them explode with the black flames covering their bodies!

“{Shadow Detonation}!”

BOOOM!

“Lee! Where are you?! Enough of your cowardice, you bastard of a snake!”

Although Jack seemed to have a cold temperament, he was actually very hot-blooded. All this stress was making him madder by the time.

Even when he had snacked on Neberius several times, he was unable to absorb any more demonic energy from the same target and was only able to copy his Wings and Legs.

To acquire more of his powers, he would need to devour the whole thing, but because he kept regenerating and using whatever the hell a {Radiance} was, that was becoming increasingly difficult to pull out.

“Hahaha! Why are you looking so desperately for me?”

Lee’s voice resonated around Jack.

“You should be looking out for your own back, Jacky!”

“I’ve had enough of you, human!”

Suddenly, Neberius appeared right behind Jack at lightning speed, his {Radiance} growing much stronger than before! His Aura erupted as the demon decided to sacrifice most of his energies, knowing this environment supplied him with enough of them.

“{Reckoning of Darkness}!”

Neberius activated his strongest ability as darkness encompassed Jack completely, a Darkness that clashed against his own Shadows, which he couldn’t control.

FLUOSH!

“Ungh..! W-What is this- ARGH!”

Jack suddenly noticed that wherever the darkness touched him, he would begin to turn into darkness, being assimilated into Neberius' ability.

“I’ll extract all of your powers and become stronger, human! CRAHAHAHA!”

As Neberius laughed and engulfed Jack with his powers, Jack’s several abilities were channeled at once as he combined their effects.

Black flames, black frost, divine power, and demonic power—all of them gathered in the tip of his sword as his muscles grew several times larger and he completed his transformation fully into a werewolf!

“{God Devouring Sword}! RAAAHHH!”

His Sword transformed into the shape of Fenrir’s head, opening its jaws and devouring anything in front of him!

SLASH!!!

Neberius' powerful technique was split into two halves, where Jack swiftly leaped out, his sword reaching the crow-faced bastard’s head, soon to behead him! Neberius was too startled to react in time; his technique cost him too much energy, and his body felt completely paralyzed!

However…

“SHAAAAH!”

A mass of crimson energy gathered around Jack and Neberius; three gigantic, crimson-scaled hydras materialized around him, biting his arms and legs, and another quickly reaching his head!

“LEE! YOU BASTARD!”

Jack roared as his limbs were torn apart at the very moment he fully concentrated on slaying Neberius! Lee was doing as he pleased, conveniently helping the enemy just to make Jack more miserable.

"Now, Crow Face! Kill HIM!”

Lee’s voice came from behind Neberius. The demon was confused about what this human even meant, but he took the opportunity anyway! His claws gathered his Demonic Energy, reaching Jack’s chest and piercing it!

“Thank you for the opportunity, foolish humans!”

CRAAASH!

“Urgh?!”

Jack’s chest was punctured by Neberius' claws as the demon attempted to grasp both his lungs and his heart and make them burst at the same time!

“Now die, you damn human!”

His Darkness emerged out of his {Radiance} once more, this time thanks to the Demonic Energy in the environment, which made him naturally even stronger.

He attempted to fill Jack’s wounds with his darkness to blow him into pieces from the inside out, noticing that even crushing his lungs and heart didn’t quite do it!

“Y-You bastards…! All of you… always… fucking with me…”

Jack started muttering those words as Neberius and Lee coordinated their attacks, about to make sure Jack could no longer regenerate!

“JACK!”

He could hear Fenrir’s voice within his mind, but his screams were growing fainter.

“Do it…”

Amidst the darkness that connected both of their souls, Jack’s eyes shone with crimson light as he opened them within the endless shadows.

“What? But…!”

Fenrir emerged in his seamless, true form, an endless sea of shadows with a gigantic wolf-like head, wrapped in countless chains.

“I’m already Max Level! Get over it and devour me, Fenrir! NOW!”

Jack’s screams resonated within Fenrir’s soul. Because of the butterfly effect both of them were unaware of, Jack was being forced to constantly fight even stronger foes than he was supposed to.

And right now, while fighting these two monsters, he simply couldn’t properly keep up!

Fenrir acknowledged his resolve, but he didn’t refute his order; he knew that if he doubted, Jack and Fenrir would die as their bodies and souls were crushed into pieces.

“DAMMIT! FUCK!”

Fenrir was filled with frustration over the technique Jack asked him to use as a last resort, one that can only be used in the direst of situations.

And that was to devour Jack whole, triggering their “perfect fusion.”.

However, this perfect fusion came with a terrible flaw.

“RAAAAGGHH!”

Fenrir’s enormous jaws surged from Jack’s shadows as he approached his maws to engulf Jack whole, surprising Lee and Neberius at the same time.

“What is that damn wolf trying to do?!” Lee wondered. His swords were about to cut through Jack’s neck! “Lord Uroboros!”

“S-Stop…! STOP HIM AT ALL COST, LEE!”

Uroboros himself panicked, quickly making Lee take things much more seriously. His speed was hastened as it felt like time itself was going incredibly slowly.

He moved faster across midair, his swords about to cut through Jack’s neck while his snacks held all his limbs in place!

At the same time, Neberius was going to burst his chest apart, which would make the kill even more guaranteed!

Yet.

Jack was devoured much faster than them; it was almost instantaneous!

The moment Fenrir devoured Jack again, the two went through a similar experience to their first contract.

It felt as if Jack was completely disintegrated and then reborn within Fenrir’s endless darkness, embraced by it and fusing with the wolf’s and even his own chains, wrapping around his soul.

A cocoon of darkness was formed where he was left, accompanied by a mighty shockwave exuding Cosmic Energy, sealed deep within Fenrir’s Soul!

RUMBLE!

“Uurrggh…! We didn’t make it in time!” Lee cried in frustration.

“CRAAAH?!” Neberius was blown away by the shockwave alone.

The cocoon of darkness started to slowly beat, as if there were a large heart within; something was being formed inside at an incredibly rapid speed.

And within Jack’s mindscape, the darkness that composed Fenrir engulfed him more and more; his crimson eyes glanced into his own soul.

A part of it was beginning to slowly disappear, and with it, his memories and emotions.

Fragments of such memories showed up in front of him one last time—the laughter of his father and the smile of his mother.

Of Anna when she was just a baby, being carried by his mother’s arms...

Each memory shattered like pieces of glass as Jack’s crimson eyes couldn’t stop crying.

The price to pay for this form was his soul, emotions, and memories.

If he overused such a power, eventually he would stop being Jack and become just Fenrir.

This was Fenrir’s ultimate plan, but now even the wolf mourns Jack’s sacrifice.

Because he had grown to love him as his family, and also all those around him...

“I’m sorry… Jack.”

He couldn’t stop this; the more they melded as one, the more Fenrir would devour Jack’s mind and memories.

This was one of the things that caused Jack to grow increasingly colder and more emotionless as the story of Solo Player advanced.

And one of the things Anna hated the most.

Because at the end...

“It’s fine…” Jack smiled. “I’ve only lost a couple of weeks of memories, nothing too bad... I will simply make new ones once we survive this.”

“Still…” Fenrir sighed. “I’m sorry that-”

“Enough, I’m not used to your soft puppy act, let’s wreck these fuckers and end this! I don’t give a fuck anymore!”

Jack was filled with more wrath and resentment than Fenrir himself. The Wolf that once tried to fight against the Nebulas, the Strongest Gods, was being overwhelmed by a mere human!

“You’re right… Let’s fuck them up!”

Crack, crack…!

The Shadow Cocoon started gaining countless cracks, slowly beginning to open up, as Lee and Neberius rushed toward it, their powers, and weapons on hand!

“Lee, destroy the cocoon before it’s too late!” Uroboros ordered Lee. “That bastard of Fenrir is trying to Unseal even more of his Powers by increasing his Assimilation Rate over that Human’s soul! DESTROY THE COCOON!!!”

“Yes! Master Uroboros!” Lee roared, putting all his will into it when it came to serving his one and only master. His entire body suddenly shifted, gaining a larger frame, more muscles, crimson scales, a long snake-like tail, and multiple arms! “{Twin Snake Sword’s Demonic Dance}!”

Swinging his two swords and several other swords made out of crystalized demonic energy, Lee spun in midair and reached the cocoon, clashing against it with all his might!

“I’m sorry, Jack! But our little battle will have to come to an end NOW!”

SLASH! SLASH! SLASH! SLASH!

“CRAAAH! {Abyssal Feather Blade Storm}!”

Neberius already figured out that working with the human blessed by Uroboros was a better idea, even more, if he could get benefits out of it later by becoming Uroboros Right Arm.

Without even doubting it anymore, he attacked alongside Lee, joining forces with him as his feathers flew out of his body, resembling thousands of blades slashing through the Shadow Cocoon and then exploding!

BOOM! BOOM! BOOM! BOOM!

The Shadow Cocoon’s cracks continued to spread as it took all its hits at once until it began to crumble apart! Lee and Neberius smiled viciously; it worked! His Evolution was interrupted!

“GRRHHHH…”

Or was it?

Amidst the crumbling Shadow Cocoon, the giant paws of a black wolf surged from within them, tearing apart the entire cocoon before it could fall apart.

CRASH!

And the enormous figure of an over-five-meter-tall black wolf emerged from within, with two sharp black horns decorating its forehead and four crimson-red eyes, along with three tails and incredibly sharp claws.

The wolf’s very presence sent shivers down Lee and Neberius at the same time; their plan failed in the very last minute, and this time, Jack was even channeling Fenrir’s Cosmic Energy.

“Our Second Evolution is complete…” Fenrir’s voice echoed within Jack’s mind. “We’ve finally unlocked the ability to use some of my Cosmic Energy, Jack!”

However, he received no response.

“Jack?”

Jack’s mind had blacked out, unconscious after his memories were torn apart from his mind.

“Tch…!”

Fenrir wanted to say a million things, he even wanted to curse the heavens…

But he was better at doing what his friend left him to do!

“I’LL FUCKING TEAR YOU TO SHREDS…!”

Around Fenrir, the very Chains that had Sealed him surged from his Soul! 

FLASH!

“T-Those are…! The Cosmic Sealing Chains?!” Asked Uroboros in utter shock.

“W-What’s that?!” Neberius didn’t know about them; he wasn’t a Constellation yet.

“You know, snake?” Fenrir suddenly spoke. “I’ve noticed that, as I unseal my powers, the chains that are left loose... I can control them.”

The chains quickly reached Lee and Neberius, and the two desperately evaded them!

CRASH! CRASH! CRASH!

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