His heart began beating faster and faster. Because, the size of the box was rather familiar to him. His hands ripping open the box became far more urgent.

'As I thought!'

Jin-Woo's eyes grew wider. There was a golden key inside the box.

Indeed, it was the key to an instant dungeon, the one he'd been anxiously waiting for.

The information on the key appeared soon afterwards.

Tti-ring!

[Item: Key of the Demon's Castle]

Rarity: S

Category: Key

A key that will let you enter the 'Dungeon: Demon's Castle'. Can be used at the Daesung Tower located in Songpa-gu, Seoul.

"It's an S?"

Jin-Woo raised his voice in surprise.

Of course, there was no guarantee that the rarity ranking had any bearings on the difficulty of the dungeon. But, he couldn't think of it any other way.

The rarity 'E' key opened a dungeon that was on par with a Gate ranked E, after all.

What would he do if the difficulty of the instant dungeon turned out to be 'S', then?

Even with a raid team consisting solely of S-ranked Hunters, there was no definite guarantee that such a dungeon would be cleared.

The odds were around 50:50?

The difficulty of a Gate exploded upwards past the rank B, and even when looking through the entire world, there had been too few cases of S-rank Gates opening up in the world.

'One of them appeared on Jeju Island, though.'

Afterwards, the island of Jeju became an abandoned hellhole where no humans could exist.

Jin-Woo stared at the key in his hand for a long while.

'This is what I really wanted?'

If there was one silver lining to be found here, then that would be the explanation saying he'd be able to 'enter' the dungeon with this key, unlike the previous one which said he'd be 'transferred' instead.

The implication being that he could escape at any time if he felt like it.

Even if the key suddenly vanished from him, he still had the return stone from the last dungeon waiting to be used inside his Inventory as well. He was no longer worried about getting trapped behind an invisible wall like the last time.

'I've worked hard to earn this chance, so I can't throw it away like that now, can I?'

He simply had to confirm right away with his own two eyes whether this was what he really wanted or not.

Part 2. Demon's Castle

In front of the Daesung Tower.

A super-tall skyscraper over a hundred floors tall was standing straight as if to pierce the heavens above. Indeed, this was what the modern skyscraper should look like. Just looking up at it made him feel extremely dizzy.

There were only a few people walking around as it was already late evening now. The streets with not one soul on it gave off an eerie vibe.

'Still, I can't be sure, so....'

Jin-Woo took a good look around him, before pulling up the hood attached to his top to hide his face.

If someone saw a person disappearing and appearing again in thin air without a Gate around, that might cause a bit of ruckus. Not only that, there were several CCTV cameras installed here and there in the near vicinity, so it wasn't such a bad idea to avoid being too conspicuous.

….Actually, there was someone busy eyeing Jin-Woo right at that moment.

'Who could that kid be?'

To think, there would be a straggler wearing a hoodie busy loitering around the building at this time of the night....

The security guard watching on from inside the building found Jin-Woo's behaviour rather suspicious and stood up from his chair.

However, as this guard walked towards the door, he couldn't help but come to an abrupt stop and his eyes opened up real wider.

"Wha-what the heck?!"

The security guard gasped out in a surprise and hurriedly ran outside.

The man was definitely walking towards here, yet he had vanished from the view, just like that. Utterly without a trace.

The security guard searched around his vicinity, but he couldn't even spot an ant here.

He tilted his head this way and that, before turning around.

"Well, I'll be.... What a baffling thing that was."

The security guard was about to go back inside the building, but then, caught something in the corner of his eyes, and turned his head to see what it could be without thinking.

"U-uwaaahhk?!"

He cried out in shock as he fell hard on his butt.

"What, what, what the heck is going on here?!"

The security guard cried out with a pale face.

A person's disembodied hand floating in the air then vanished once more.

*

Jin-Woo retracted his hand.

'It's connected to the outside world.'

Unlike the last time, there was no invisible wall blocking his exit. The key also didn't disappear and remained tucked inside his pocket. If he wanted to, he could get out of here at any time, in other words.

'Now that I'm finished with confirming the escape route...'

Since he didn't know whether the rarity of the key equated to the difficulty of the dungeon, he was far more cautious than usual.

Jin-Woo pulled the hood back and took a look behind him.

"..."

It was a sight shocking enough to make him groan. Just now, when he was taking a few steps towards the Daesung Tower, the world in front of his eyes transformed in an instant.

Could this place even be called a dungeon anymore?

A completely different world was waiting for him.

Instead of the vanished Daesung Tower, a massive tower-like structure stood there.

'Wait, is that really a tower, or should I call it a castle, instead?'

A tower rising up high into the air without an end, wrapped in reddish black flames. It was as if the tower wasn't burning, but it was spewing out billowing flames, instead.

"A burning tower, huh."

Rather than the name of 'Demon's Castle', maybe that nickname suited it better. Jin-Woo slowly walked towards this burning tower.

Crackle! Pop!

The closer he got, the louder the noises of flames rampaging around grew.

'Can I even enter this thing in the first place?'

However, even if he did, there was yet another problem to consider.

Just like the last instant dungeon that was based off on the subway station, there was a good chance that, since this dungeon was based off on the Daesung Tower, he'd have to climb up 100 floors to clear it completely.

He couldn't even begin to imagine just how long that would take.

'Mm?'

Jin-Woo's steps came to a halt. He sensed a strong aura near the entrance.

He slowly surveyed the surroundings and spotted a black lifeform the size of a bull huddled in slumber right in front of the doorway.

Jin-Woo carefully summoned the Poison Fang of Kasaka.

Tti-ring.

[Item: Poison Fang of Kasaka]

Rarity: C

Type: Dagger

Attack +25

A dagger fashioned from the poison fang of the Kasaka. There are traces of the Kasaka's poison on it, so when attacking, it will cause Paralysis and Bleeding status effects. Can be stored in the Inventory, or can be sold at the Store.

Status effect 'Paralysis': the target will be unable to move. Success rate is fixed.

Status effect 'Bleeding': the target's stamina will be reduced by 1% per second.

Its attack power wasn't all that high, but the greatness of its added effects was proven in real battles time and time again.

'It'd be nice if the Paralysis works and I get to kill it easily.'

Jin-Woo walked as quietly as possible while approaching that creature. However, it was impossible to fool the olfactory senses of a monster. Soon enough, the creature sniffed the air and raised its body up.

'Che.'

Jin-Woo clicked his tongue.

The creature stood up completely and all three of its heads turned in Jin-Woo's direction.

[Hell's Gatekeeper, Cerberus]

It was a huge dog possessing three heads. The name written in red letters floating on top of its heads immediately drew his attention. It was proof that the monster's 'level' was very high.

'Since it's red, does that mean it's around the same level as those centipedes from the penalty zone?'

Back then, he managed to barely run away from the centipedes. Well, he was only a level 1 back then, so it couldn't be helped.

'But, it's different this time.'

He had grown stronger quite quickly during the short space of time.

Without a doubt, that black creature was strong, but still, it didn't come across as truly overwhelming. His enhanced, alert Perception was telling him that he could do this.

It wasn't for nothing that he raised his Perception Stat. He kept on investing points to this Stat so he could easily tell whether he should fight or take flight in cases like this.

"Growl!"

The Cerberus sensed the enemy and bared its fangs to threaten him.'

Jin-Woo's gaze then wandered off to the creature's tail. It kind of resembled a whip, and its end was enveloped in flames as well.

Jin-Woo's eyes sharpened in an instant.

'Fangs and a tail. At the bare minimum, two methods of attack, huh.'

Jin-Woo swallowed his dry saliva.

The Cerberus slowly closed the distance before stopping right in front of him and began studying him for some reason.

'Is it... looking for an opening?'

Just as he thought that....

The monster attacked him.

"Rowr!!"

Jin-Woo's eyes opened much, much wider.

'Too fast!!'

Jin-Woo barely evaded the Cerberus's fangs by sliding underneath the leaping monster.

The Cerberus landed back on the ground and spun around, before began biting at him with its three heads.

"Woof!! Bark!! Rowr!!"

The sharp fangs gleamed coldly in between the biting snouts.

Tti-ring!

['Title: Slaughterer of Wolves' buff effect has activated.]

[Title: Slaughterer of Wolves]

A Title given to a hunter skilled in hunting wolves. When facing animal-type monsters, all of your Stats will increase by 40%. (TL: Again, the 'hunter' is a lower case here, because it literally means someone who hunts, while the 'Hunters' up until now had been written in English and is a specific job title of those who hunt monsters from dungeons.)

He sensed his body getting lighter.

'Nice!'

Jin-Woo quickly retreated and wielded his dagger at the Cerberus as it continued to stick close to him.

Swish!! Swish, swish, swish!!

Clang!! Cling, clang!! Claaang!!

The dagger collided with the fangs and issued loud noises.

The blade moved at a blinding pace, yet all he could do at the moment was to deflect the Cerberus's attacks and nothing else.

'Even after I buffed up, it's still this strong?!'

The Cerberus's Agility had easily exceeded his imaginations.

In order to overturn this situation, Jin-Woo activated his 'Intimidation' skill.

['Skill: Intimidation' has been activated.]

[The effect has been cancelled due to the high resistance of the target.]

Jin-Woo's eyes widened.

'It didn't work?!'

It was at that moment that the long tail of Cerberus flew in like a whip.

Whoooosh-!!

Jin-Woo reflexively ducked his head lower and evaded the tail. But that caused his legs to stop moving for a second. And the monster didn't miss this opportunity.

One of its heads powerfully bit into Jin-Woo's left shoulder.

"Uwaaahck!!"

Jin-Woo summoned all of his strength and stabbed the dagger into the middle of the biting head.

STAB!!

['Effect: Paralysis' has been activated.]

[The effect has been cancelled due to the high resistance of the target.]

['Effect: Bleeding' has been activated.]

[The effect has been cancelled due to the high resistance of the target.]

"Whimper!!"

The Cerberus cried out and let go of him.

Thankfully, he was able to minimise the damage done before other heads had the chance to join in on the attack, but his left shoulder was now in tatters.

What a scary biting power that was.

He tried to move his left arm, but it didn't want to budge. Jin-Woo's expression crumpled unsightly.

He managed to wound the Cerberus, but when comparing the severity of their injuries, then it was clear that he came off far worse in that exchange.

'If either of Paralysis or Bleeding worked, the situation would've been different by now....'

Jin-Woo glared at the Cerberus and clicked his tongue.

Then, something else happened.

'Huh?'

The eyes of the Cerberus were being dyed in a crimson colour all of a sudden.

"Grooowwl."

Inexplicably, Jin-Woo sensed something ominous was about to happen.

'What could it be?'

[Hell's Gatekeeper Cerberus is using 'Skill: Rage'.]

[Its state of rage will persist for the next three minutes.]

[All of Cerberus's Stats will be increased by 100%.]

[Cerberus will no longer feel pain.]

Jin-Woo cried out.

"What did you just say?!"

A monster just used a skill!!

In that instant, the Cerberus leaped off the ground.

'F*ck!!'

Even before he could react, the Cerberus appeared right before his eyes. He hurriedly swung his dagger, but it only managed to graze the side of one of its heads.

And all three heads bit into Jin-Woo simultaneously.

Kwajeek!!

"Euheuheuhk!!"

Jin-Woo gritted his teeth. His neck, waist and thigh all got bitten.

The Cerberus ran at its top speed and slammed Jin-Woo against the castle's gate.

SLAM!!

Jin-Woo's HP hit the rock bottom in an instant.

"Keo-heok!!"

[HP: 411/3,602]

Tti-ring!

[Your HP has decreased below 30% and 'Skill: Tenacity' has been activated.]

[All damage received will be reduced by 50%.]

Thanks to the damage reduction and the Tenacity passive, he was able to avoid getting killed in one hit.

"Keuh...."

Jin-Woo's eyebrows shot up in anger.