For 10 minutes both lux and David explored half of the dungeon, even with their speed, only half was explored.
For the past 10 minutes, they encountered various kinds of monsters inside the dungeon like lizardmen, golem, orcs, and dragons.
At first, lux was surprised after seeing a dragon and thought it was the dungeon boss but he knew what the real boss was after seeing the book from david so he threw those thoughts away.
If this was a game that dragon is considered as a mini-boss, and it's power is estimated to be S Rank.
They only explored half of it but an S Rank monster appeared already, which means that this dungeon is not classified as SS Rank but a higher level which is legendary rank.
Currently, there are 12 types of dungeon difficulties based on how strong the monsters are inside like, F-rank, E-rank, D-rank, C-rank, B-rank, A-rank, S-rank, Ss-Rank-, SsS-Rank, L-rank, M-rank, and Dv-rank.
F-rank is the weakest while Dv known as Divine rank was the strongest.
The government's and all leaders warned their people to not get nearby or raid these Dungeons who are classified as divine rank, not because of how strong the monster's insides are but because the boss inside is a demigod which is practically impossible to beat for the current humanities.
These demigods can destroy the world alone if they want to do it, luckily these demigods don't like destroying things without reason and remained dormant for thousands of years.
There are only 7 dungeons classified as Dv-rank, the people called it the Seven wonders of the world.
Some people from the past tried to challenge these dungeons but end up failing and was the cause of the destruction of 9 out of 25 continents in the world.
The destruction of the 9 continents made people fear to the point that no one ever dared to challenge it anymore.
(Explain it later why the world has more than 9 continents)
...
David was the one who estimated the dungeon ranking since he is a person who knew quite a lot about dungeons through reading books.
After seeing the dragon, he instantly knew that this dungeon is L-rank based on what he saw while investigating the dungeon.
L-rank - Dv-rank dungeons are like a labyrinth because of how complicated the passage is, it's like a root of a tree, and every dead-end has miniboss, the deeper you go the stronger they get.
It's been 5 minutes since they passed the dragon and they couldn't find any monsters in the vicinity anymore, they also noticed that there are no other routes like earlier.
The path only leads in one direction which means that they are near the boss room, David realized this and told lux. -"it seems that we are near the boss room"
"Since you said it, all we have to do now is to record the monster inside for a few seconds and retreat"- lux.
David nodded and speed up a little bit.
While speeding up, both of them felt a sinister aura.
They stopped running forward to check what was in front of them.
Lux and David had a solemn look while observing the area.
" do you think we are next to a boss room?" Lux asked.
"I don't think so, this aura is different from that monster. Anyway hide your presence it's coming on us" David noticed the incoming monster.
Hearing that, lux immediately hides to a rock nearby just in case the invisible effect wears off. David did the same from the other side, no one knows when it disappears. They have 2 more invisibility potions in their pocket but they are only allowed to use them after the effect wears off in 5 minutes because Wilbur told David not to use them continuously. After all, it might have bad side effects later since it's not complete yet.
Bang... Bang... Bang... Bang... Bang...
The grounds shake as it walks on the ground and a loud sound of the foot can be heard as it touches the floor.
The sound gets closer as it walks towards them and they can now sense it's presence like it was next to them.
"..."
Both Lux and David did not take any action or create any sounds that could indicate their presence while it was close to them.
The two clearly know that their opponent is not a normal monster based on what they sense. If lux want to describe what kind of monster is about to appear it must be a gigantic one because of how it can shake the ground by just walking.
Rumble... Rumble...
A gigantic 30 meters black monster made out of dark-looking mana with a massive sword on it's back made its entrance.
It seems that it didn't notice the presence of the two since it's just walking without showing any reaction of noticing any intruder.
Without making any facial expressions, lux glanced at the monster using his two eyes without blinking.
On the other side, David couldn't believe the monster that appeared was a shadow knight.
Damn, to think I see this monster here. Lux may not know this but, this monster can kill someone no matter how strong they are just by walking next to them. The body of this monster is made of shadow, nor is it a normal shadow because the shadow it emits can kill a person nearby just by walking next to them. The only way to survive is to become the death itself or have the power to oppose it like light energy. In ancient times, shadow knights were originally created by the God of death and sent to this world to annihilate mankind but, they failed because the people fought with the help of other gods. the remaining death knights were punished by God of death for failure by forbidding them to return to the realm of death. ' David explained death knights through his thoughts.
While the death knight is passing them, David hopelessly stared at lux hoping he's still alive but because of the rock and the passing monster he could not see lux situation on the other side. He wants to save him but it's already too late because if he takes any action now it will only make the situation worse, all monsters would target them if they get caught.
If lux has light energy from him, it should've created a reaction now but so far no reaction of light energy opposing the death energy happened, which means he has no light energy which makes David feel anxious.
David hopelessly looked at lux as the death knight passed by.
a few minutes after the death knight passed them...
David checked the surrounding area to make sure that the death knight is not nearby anymore before recovering lux corpse.
Knowing that it's not nearby anymore, David quickly runs towards lux, but, before he could do that...
"That surprised me, I can't believe there's a monster like that living in this dungeon." Said lux as he appeared next to a rock.
"..."
David wants to say something but it's probably impossible for now.
Lux who appeared looked at David only to see him having a weird look. "What's that weird look?" He asked.
David took a few seconds to come back to his sense before replying.
"No nothing, I was just shocked to see that monster here" he lied and denied what his thoughts want to say like 'how the hell did you survive?'.
(The sus one here is him though)
"Then, Let's go now, we don't have time" said lux.
David nodded and they both went further without questioning each other.
...
In a few minutes, lux and David arrived at the boss room, it's also when the invisibility effect expired.
Without any invisible effect, lux and David look at the massive room in front of them with a solemn look after seeing the monster laying on the ground.
The room has a crater on the ground where the massive monster is sleeping.
Lux muttered a word after seeing the monster. "So that's the dragon snake huh, the SsS-rank monster"
The dragon snake is a 5 kilometers Snake with wings just like a dragon.
This massive monster could devour a city in a few minutes if it decided to do it and this snake is the one behind that incident earlier, the one who controlled those orcs.
For now, it seems to be sleeping because if not it would have noticed lux and David's presence earlier when they arrived.
"Now that we recorded its existence we already finished our mission, all we have to do now is to wait 5 minutes before going back" said David as he sat on the ground like he is not interested about the monster.
Lux is a bit suspicious about his behavior but it's not like he cares about his personal things and nodded shortly.
Lux got bored while waiting for 5 minutes and tried to look at the surrounding area to find some interesting things besides the monster sleeping on the ground.
David was a bit curious about lux after seeing him checking the area around. "Is this your first time seeing this kind of monster?" He questioned him.
"Not really, I once saw a monster like this one 8 years ago" he honestly replied.
"Is that so, if I recall what happened 8 years ago it was during the monster invasion. now that I think about it you don't look scared about that monster, what if it wakes up now?" He made a joke to scare lux but David was surprised to hear him answering honestly and tried to question him more to get more information about him.
Lux didn't reply for a few seconds, he clearly knew his motive for asking these questions and told him "I'm not really afraid about monsters no matter how strong they are, also, what about you?" He returned his questions by asking the same question.
...
"If you are asking about it, we're the same I also saw that same monster 8 years ago, that monster that almost destroyed the country before, luckily some people who called themselves a hero sacrificed themselves to protect the country otherwise the outcome would be different." He answered.
Lux got a serious look after hearing what he said. 'This guy, he doesn't really care if those people 8 years ago protected the country, because what he really meant is what kind of action would we take during that time, whether I decided or he decided to save it or not, it means we could kill it during that time when we were still a kid but, although It could also be a bait to get any information about me, he might be lying right now so replying any further would be risky. This man is not just an ordinary person, he might also be someone from another world like me' lux said to himself to be aware of David's existence.