Blue Planet, Year 2159.

At the heart of the Forbidden Land stands the towering Archaic Mountain, exuding an eerie energy that instills all who venture near with fear. Within its labyrinthine lair dwells the formidable Void dragon, a force known to be the strongest demonic beast.

Yet, despite the omnipresent danger, legends persist in fearless heroes who seek to challenge the demonic dragon's dominance and liberate the land from its malevolent grasp.

Den and his teammates are the strongest mercenary group in the Human Domain. Their group Elpizo Mercenary, whispered with reverence giving hope to humanity as they are currently fighting the tyrannical demonic dragon, preventing the catastrophe that will unfold soon if they fail to slay the demonic beast.

Inside the boss room, a symphony of chaos emerged. The metallic resonance of shields mixed with the heavy steps of brave fighters, combined by the crisp incantations of magic spells and clashing of swords, created a song of battle that echoed within the chamber, thus, infusing it with an intense energy.

"Give it your all! Activate all your skills! The boss is about to die!"

Den shouted, instructing his team.

While the boss was busy dealing with the tank of his team, Den gathered his remaining strength to jump high and activated his strongest offensive skill 'Blade of Execution' to end the life of the struggling Void dragon.

In a swift vertical motion, Den's hands wielded the sword, guiding it downward with a powerful divine light, enough to cut the head of the demonic beast all the way to its menacing mouth.

The dragon received much damage and coupled with the wounds it received previously, it finally fell to the ground making a loud thud sound.

Pant.

Pant.

"We did it!"

The people unitedly sang in joy despite their critical injuries. All the years of their hard work paid off.

Through years of relentless perseverance and against all odds, they transformed from being weak to an existence capable of conquering the Forbidden Land, defeating the legendary Void Dragon— the strongest known demonic beast on this planet!

Truly a majestic scene to commemorate!

"Let's rest up before leaving," Den sat in the corner. "Search and collect the core Alastor," he said before closing his eyes to catch his breath.

Alastor excitedly walked into the dragon corpse, after all they did not get any core in a while.

Upon arrival at the corpse, the man frowned.

"Leader! We didn't get any rewards!" the Vice-leader Alastor shouted as he ran to Den.

"Huh?"

Den was shocked by the sentence exclaimed by Alastor. He walked near the dragon corpse. It indeed does not have a dragon core.

"Do you have any idea, Alastor?"

Alastor, the vice-leader of Elpizo is the intelligent agent that holds the various information for the group to utilize.

"This is just speculation but I have an idea," Alastor said as he slowly walked towards Den. His eyes became red, a big smile forming slowly in his pale face.

"This!"

Suddenly, Alastor stabbed the person in front.

Den wanted to react but his body couldn't move because of the fatigue and several heavy injuries he accumulated during the raid. He can clearly feel the blood gushing out of his stomach and the wild face of Alastor.

The world turned silent for a second.

"You didn't expect this do you? Deeeen?" Alastor shouted crazily. "You didn't know how long I prepared for this moment! We are tired of being your shadow!"

'Ha... I'm very pre-occupied to save the humanity that I didn't even know the feelings of my teammates,' Den thought silently while he observed his teammates smiling widely.

'So this is a hero. They always die at the end,'

Chuckling inwardly, he looked at Alastor with sympathetic eyes, "You know that I will not die from this stab right?"

"Time Rewind!"

This is his trump card skill in case anything accidental happened to him. It can rewind the time by 10 seconds and have a 1 day cooldown. Den smiled after that but nothing happened.

'What? What's going on?!' Den desperately shouted in his mind.

"Khuu..khu... AHaHAaHaHAHaHAHAHa!"

Alastor almost cried laughing because of what he heard. "Are you really an idiot, Den? You didn't know that this place is isolated in time! It means that this room has no past nor future!"

'Dam*it! He got me!' Den was on the verge of collapse but he remained composed.

"You are really strong, Den. The strongest of all chosens!" Alastor shouted with envy, "I admire you for being calm in this situation," he turned around, walking a few steps.

Suddenly, he stopped and rotated his body to face his pitiful leader.

"You are blessed with the strongest skills and strongest allies. You have all the traits of... what is it called? hmm..."

Alastor paused for a second before exclaiming.

"Right, right! A Hero! But you know Den? you are too kind! That's why you are going to die here today!" Alastor mocked, followed by the laughing of his fellow teammates.

Den couldn't believe what he was seeing and wanted to refute. "I said that this mere stab won't kill me—"

"Shh Shhh Shhh! The demonic blood of the dragon clone is slowly circulating into your body. Just die quietly, alright?" Alastor interrupted, before collecting the body of the dragon.

Hearing what Alastor has said, Den silently admitted that Alastor is way smarter than him. He is simply a strong kind warrior with common wits.

'I see, even if I survive this situation. The humans will view me as a Demon, a race that I, the strongest chosen, hated the most. Even if I try to ally with the demons to get my revenge, they will likely kill me because a lot of their kin were slain by me,' Den thought silently as he gritted his teeth.

"You bastard!"

Den shouted in desperation. He knows that he will never get out of the fate that befall upon him.

"Ah right! thanks for killing the boss leeeaaader. Bye, bye," Alastor waved after turning around with the team following suit.

...

Ten minutes passed since that event and Den is slowly crawling on his deathbed.

'At least humanity is saved,' Den smiled.

He wrapped his mind with mana to decrease the rate of the corrosion of demon thoughts.

While imagining his peaceful end, a thought suddenly came into his mind.

'No, there is no core in the boss! This means that there is still the final boss left!'

'Fighting that Void dragon clone took a toll on us, we almost died... then, what about its real body?'

Den sighed.

'Alastor really is intelligent, he already calculated that there is no saving humanity and it's logical to live life with fame and power but because of my stubbornness, they will never get to live that life.'

'Being my shadow means that they have to follow me no matter what.'

'Was I wrong?' Den asked himself.

'Why did I even try to save humanity? What was my hard work for?'

"No! This can't be! Evil will never be victorious!" he shouted. He made up his mind to punish evil.

'Alastor you smartass. With the situation I am facing, even when you look at all of the angles, this is a checkmate.'

'Fortunately, he didn't know that I still had one move,' Den smiled bitterly.

"System! How long before my mind becomes corrupted of demon thoughts?"

That's right, System is Den's secret that Alastor didn't know or rather no one knows except Den himself. It helped him throughout his journey.

[2 minutes and 43 seconds] System replied.

'That is plenty. One of my trump skills 'Soul Purify' is a consumable skill that only takes 10 seconds to replenish my body with negative effects but that will not solve my problem. The demonic blood of a Legendary ranked dragon, on the verge of evolving to Mystic rank, is not that easy to solve. At the very least, it will prolong my lifespan for months but after that, I will be demonized.'

Sigh.

'Dragon demonic blood surely is troublesome. It contains ancient demon thoughts that you can never get rid of.'

Faced with the grim reality, Den made up his mind.

'It's better not to delay my death than to suffer meaninglessly.'

"I guess this will be my end," Den looked up and closed his eyes.

"System! I will sacrifice my soul to transfer you into a form of a book where my memories and skills will be contained. Can you do that?" Den firmly asked.

[It is possible. This will cost your existence and the system will proceed into hibernation due to exhaustion. Please Confirm.]

Seeing the prompt, Den sighed in relief.

"Confirm!"

Suddenly, his whole body produced light, illuminating the dungeon room.

A scarlet book materializes and hovers weightlessly in the air with ancient patterns and time-worn symbols on the cover, giving it a majestic allure that bathes in a faint glow.

As if guided by an unknown force, a small wisp of light fuses with the book.

After a while, the book was nowhere to be found, leaving only lingering curiosity in its wake.