If a Dungeon could be considered as a house, a Dungeon Core was the PC that could control everything in that house. However, to control it, you had to understand the Ancient Language, so most humans in this age couldn’t become a Dungeon Master. Well, even the Skeleton Mage, the Dungeon Master that I defeated earlier, could only understand the basic function of the Dungeon such as creating monsters every hour. It couldn’t understand the more complex commands to control the Dungeon. No, in fact, calling it a Dungeon Master was a mistake, as it didn’t gain access to the core part of the Dungeon. Rather than a Dungeon Master, that Skeleton Mage could only be called Dungeon Manager or Dungeon Caretaker. Or just the guardian of the Dungeon Core.

As for me, after touching the floating orange ball that was as big as my head, I immediately accessed the core part of the Dungeon Core. Naturally, it had several protections, but as a former Dungeon Master, I only needed to show the Dungeon Core my memories and my skills in managing a Dungeon to be acknowledged as its Master. Well, the process was not complex, but for people who didn’t know anything about it, it would be hell. The Dungeon Core only gave fifty questions regarding Dungeon’s management, naturally in Ancient Language, and all I had to do was answering them without making a mistake at all. Even if I made a mistake, the worst that could happen was the Dungeon would send a monster and repeated the question again, but I didn’t need to do that as I knew everything about the questions.

“Congratulations on obtaining a Dungeon, Master.” Slimerin congratulated me when the Dungeon Core acknowledged me as its Master. I was quite happy and I wanted to remodel the Dungeon as soon as possible, however…

“Insufficient Mana?”

Yep, I didn’t have enough Mana for operating this Dungeon.

Well, let me explain how a Dungeon worked a bit. So, a Dungeon was always located above a Dragon Vein. A Dragon Vein was Mana that flowed through the ground. So, a Dungeon would use that Mana from the Dragon Vein to execute its basic functions. Even I, as the Dungeon Masters, could use the Mana from the Dragon Vein to redecorate the Dungeon and summoning, or rather, creating monsters too.

However, the Mana from the Dragon Vein was similar to an army. Even though it was strong and limitless, it still needed a commander to lead it. And by a commander, I meant the Dungeon Master’s Mana. However, the quality of the Commander also determined how much it had the power to control the army. So, there were no definitive points in how much Mana needed to summon a monster or to redecorate the Dungeon.

So, without my Mana, it was impossible for me to lead the Mana from the Dragon Vein. I could only sigh at this and did the next best thing I could think of at the moment. I poured 90% of my Mana into the Dungeon Core. I could only accumulate the Mana little by little like this. By estimation, I needed another two or three days before I could use the most basic function of this Dungeon, which was creating monsters. I didn’t plan on changing this basic function though, as it would alarm the Empire, and perhaps, they would assemble a party to conquer this Dungeon soon if they noticed it was changed. That was why, for the next few days, until I was prepared, Undead would keep roaming in this Dungeon as if nothing happened to the Dungeon Core.

“Master, if you don’t mind, I can stay in this Dungeon and poured my Mana into the core.” Slimerin said after I poured almost all my Mana into the Dungeon Core. Slimerin was a type of monster and as a monster, a place like a Dungeon was the best place for her. It was because the Dungeon was saturated with Mana, so it would be better for her growth if she stayed in a place like this. Also, she could also give some of her Mana to the Dungeon Core. It was like a cycle of Mana. And if she poured her Mana to the Dungeon Core, I wouldn’t have to wait too much before I could use the function that I needed.

Speaking of which, there were many ways for a Dungeon to accumulate Mana. The Dungeon usually was located above a Dragon Vein, so it would accumulate Mana from the Dragon Vein daily. Besides that, a Dungeon could also accumulate Mana by killing other creatures that were not born in the Dungeon. Mostly, these creatures were humans who wanted to conquer the Dungeon for wealth. When any creatures died, the Mana they accumulated inside their body for years would be released to air and it was what the Dungeon accumulated for its growth. Also, this kind of Mana was what we called as Experience Points in the system.

So, usually, the Dungeon would make a lot of preparation for its growth. First, it had to protect its core in the deepest part. After that, it created monsters to protect the core. After that, to invite people to come to the Dungeon, a Dungeon would use wealth such as precious ores or rare herbs to invite Adventurers. If the Adventurers were stronger than the Dungeon, the Dungeon would be conquered and if it was unlucky, its core would be destroyed. If it were lucky, its fate would be like this Dungeon, becoming a source of resources for the one who conquered it. If the Dungeon was stronger than the people who entered it, it could kill those invaders, or it could let them go so they would attract more people.

In the past, I was using this kind of method to gather Mana in the Dungeon. Besides killing the Adventurers, even a battle in the Dungeon could generate some Mana, albeit smaller. Especially the battle between Mages, it would have a lot of residual Mana that would be absorbed by the Dungeon Core and transformed into the Commander Mana or in easier words, Dungeon Points. I never killed someone in my previous Dungeon, by the way. I lived in a peaceful nation on Earth, so killing was something that I would never do. Maybe. I didn't know about the future, so I couldn't say for sure, but in the past, I never killed anyone that entered my Dungeon.

Anyway, it was not a bad thing for people to enter the Dungeon, walking a few floors and returned with some wealth and their lives. I thought it was a win-win solution. Well, for the Heroes and the Champions, not defeating me was not an option. Their aim was to defeat me, so they couldn’t return after gaining some benefits. That was why I set a lot of traps in the deeper floors of the Dungeon.

That was, however, for my future plan. Now, I could only take a step at one time, as I didn’t have enough Mana to do what I aimed to do. Actually, I wanted to let Slimerin stay here so she would grow rapidly and she could help the growth of the Dungeon. However, the problem was that silly Goddess. If she noticed that Slimerin was gone… I wondered what she would think of.

Should I let Slimerin stay here?

“…Well, alright then. I’ll let you be the manager. By the way, don’t create any monsters, we have to accumulate some Mana first, alright?” I said to Slimerin after thinking for a second. Hm? The silly Goddess? If she asked me where Slimerin was, I would answer that Slimerin was going to gather ingredients for me. Yep, it was not a lie, as my purpose of having this Dungeon was for me to get more ingredients.

“Don’t worry, Master, I know what I should do and I shouldn’t do!” Slimerin replied. How dependable. Unlike a certain Goddess that couldn’t be depended at all.

Well, anyway, my goal for coming to this Dungeon was almost cleared, I should return to the inn before anyone noticed that I was missing. Also, while returning, I also should gather some materials in the Dungeon. I saw some herbs when I walked to this place. I was sure I could make some potions by using those herbs. Moreover, they were quite rare as none of the herbs stores sold them.

As for the materials from the monsters, let’s forget about them. I didn’t need the weak monster materials at all. Even the strongest, the Skeleton Mage, didn’t have sturdy bones for making a weapon or armor and even though it could be used in some potions, grinding the bones was tedious and I didn’t want to do it. So, I didn’t gather them at all.

As for the Monster Cores, I gave them all to Slimerin. Unlike in a game, when a monster was killed, it wouldn’t disappear and left materials for the Players to pick. If you wanted the materials, you had to dismantle them yourselves. I heard some Players were annoyed because of this, especially the girls, but, hey, it was a reality after all. Well, for them, it was a game that was too real to the point of annoying.

Anyway, Monster Core could be the weakness of a monster, just like a human’s heart. The Skeleton monsters in this Dungeon, for example, had their cores exposed and only protected by some bones. Their cores were usually located in the middle of their body, but there were some exceptions. For example, a Dragon wouldn’t necessarily have a Monster Core. Especially the stronger Dragon, they didn’t have Monster Core at all.

Alright, I would explain what Monster Core was. Monsters were created by Mana. And that Mana would be condensed in a monster’s body and formed a core. So, a core was a condensed Mana from a monster. If another monster ate the core of the other monsters, they would be powered up, so I gave all the cores to Slimerin. As for some special monsters like Dragons, their Mana was not condensed in one part of their body but spread in their whole body. That was why they didn't have any Monster Core.

Actually, I could sell the Monster Cores to the Adventure Guild, Alchemist Guild, or to other stores because the Monster Core was useful for a lot of things. It was a condensed Mana, so it could be used to power up many things. By selling the Monster Core, I shouldn’t have any problems gathering enough money to pay the tuition fee, not to mention that I also had the Bosses’ Class Monster Cores. However, that could only happen on the premise that I could sell those cores. Rather than selling them, perhaps the authority would lock me up in a dungeon because I entered the Dungeon without permission at all. Yep, there was no way for me to get Monster Cores except from this Dungeon, so, once I showed my Monster Cores that came from Undead monsters, they would definitely know that I sneaked into the Dungeon. So, after considering this and that, I decided not to sell the Monster Cores and just fed them to Slimerin so she could become even stronger.

“Slimerin, I’ll leave this place to you.” I said as I left. I returned as quickly as I could. It was still dark when I was out of the Dungeon. The guards were talking to each other leisurely. It seemed they didn’t guard against an intruder but rather, against monsters outbreak. So, I easily sneaked out under the cover of the dark.

I was thinking of returning to the inn silently and covertly, however, while I was jumping from one roof to another, I saw a scene that annoyed me a bit. I meant, a lot.

It was in a dark alley. If my memory was dependable, it should be a place that reeked of crimes. Perhaps the appropriate term for places like this was a Slum. Yes, it should be the Slum area of this capital.

This city could be called the city that never sleeps. Forgetting the Alchemists from the Alchemist Guild that sometimes woke you up in the middle of the night because of the explosions, even in the Slum, there was a lot of activity. For men whose lust couldn’t be satisfied easily but they didn’t have money, there were brothels in this area. Naturally, I believed it was easy to get a disease or two if you went to a place like this. Well, more importantly, however, was in the plaza of the Slum, there was a market. As curiosity took me closer to that market, I noticed what kind of market it was. It was a slave market.