"Welcome to my dungeon! But your exploration ends here, as you'll die right where you are, hahaha!" So an unknown undead said, lurking in the corner, but Momonga could sense its undead nature, knowing some details.
Momonga quickly turned to where the noise was coming from, and he quickly noticed a dark spirit lurking in the corner. He observed it closely from his current location and assumed that it was an undead spirit.
'Could it be that this is a vengeful spirit? Or maybe an Undead lich in some way? If so, it won't be much of a threat to me as I have high resistance to these situations due to my undead nature and overlord class.'
"Hahaha, I'm glad we can finally meet; I am the Dungeon Master, this dungeon's creator. It's a bit sad that this is the end for you, but you'll make a great undead. By the looks of your current undead form, you are powerful!" The undead lich said, a bit too confident in his abilities.
'Alright, this guy is a bit annoying... But what did he say? "Dungeon Master," could it be that in this world, each dungeon has a dungeon master who controls the dungeon in specific ways? But I'm a bit curious about how they control the dungeon, as I don't see any specific items on him that would allow him to do so. So maybe if I defeat him, I'll gain access to controlling the dungeon, or maybe the dungeon will generate an exit?'
The undead lich starts to move around as it seems he's preparing something for Momonga.
"Since you are already undead, this will be easy! I will take control of you!" The undead lich said as he cast something to take control of Momonga.
As the spell hit Momonga, nothing seemed to have happened. As it seems, Momonga had complete resistance to the said spell.
'Did he? Did he try to control me using some kind of control spell? So you think I am that weak, huh?'
"Pathetic... you are a disgrace to the undead lich race; your powers are punny in the grand scheme of things. You'll only serve me as an experiment in the end, and all your efforts will be fruitless. I'll show you how to take control." Momonga said his tone of words gives off a hint that he is not lying which shocks the undead lich and frightens him slightly.
"Huh!? I will not have that! You are merely a weak undead that can be taken control of. I just failed my casting the first time around. So here, my minions will take care of you!" The undead lich said as he summoned a group of skeleton knights, which rose out of the ground.
'More of these? This has to be a joke. If this is the strongest he can summon, this fight is already over. However, I might as well attempt to get some information out of him. I'll take care of his summons first as I don't want them getting in the way.'
"[Chain Dragon Lightning]" Momonga quickly cast the spell he used against the previous skeleton knight. Which took care of the undead lich's summons quite quickly, turning them into ash.
"What!? You took care of my minions so quickly! Impossible they are high-tier summons." The undead lich said as his ego fell apart in front of Momonga.
'Those were high tiers? They were mid-tier at best due to their weakness.'
"Now, I will ask you a few questions; how do you control this dungeon? What is a dungeon master? Where are we currently, and how do I get out of this place? If you don't answer these questions, I will make sure your death is slow." Momonga asked all these questions in a quick haste.
"Ahh! This is impossible; take this!" The undead lich ignored Momonga's questions, quickly casting an offensive spell; the spell that the undead lich said was a fireball, something Momonga didn't expect. It shot forth and hit Momonga; however, it did nothing to him even though it was a potent spell in the undead lich's perspective.
"How!? Did you resist that?" The undead lich said, so shocked by Momonga's resistance that he couldn't help but cower.
"Well, it seems that you will not answer my question. However, I will answer yours. You can't hurt me, it's rather simple, and it's because I can't be hurt by anything below 7th Tier magic." Momonga said.
'Even though my questions weren't unanswered, I feel like I'll get them answered anyways in due time. So, there is no reason for me to be wasting MP here any longer than I already am.'
"[Maximize Magic: Reality Slash]" Momonga said as he made a diagonal cut in the air sending a slash straight through the undead lich, which cut him in half.
"Impossible- my spacetime magic didn't work against it!" The undead lich said its final words as it died.
The undead lich's crystal dropped to the ground with a slight banging sound. Momonga then picked up the crystals of the undead lich, and the undead knights stored the crystals in his inventory.
'Alright, now that I took care of that, what could be next?'
Momonga looked around a bit and saw another passageway which he quickly took. It eventually led him into another large room with a massive furnace. He sensed it generated some kind of magic and a large crystal that seemed to power the whole structure.
'What is this crystal? It seems to have been deactivated recently. Could it be that this crystal depowered once I killed the undead lich?'
Momonga started to think of some possibilities but then turned to the furnace and inspected it.
'What could this furnace be? It seems to be generating some type of dark magic. Could this be what is powering the undead monsters in this place? Should I destroy it?'
Momonga reaches toward the furnace, attempting to see what it could be generating, which he senses the dark presence.
'Indeed, it generates a type of dark magic, so I presume it is best to destroy it.'
"[Greater Break Item]" Momonga casts a spell that makes the furnace immediately collapse before him. However, right when the furnace gets destroyed, it starts to let out a massive amount of energy. Still, Momonga ignores it since he predicted that it would happen.
Momonga then goes back to the crystal slighting picking it up. However, something unexpected happens as the crystal glows a bright white color and disappears, which shakes Momonga slightly as he doesn't know what happened. But after a few seconds pass by, something appears in front of Momonga ["Dungeon Master Title Achieved"]
'Dungeon Master? Did I achieve a title from that crystal? Does that mean I'm a dungeon master now?'
A few more seconds pass as Momonga looks through what happened, and he figures out something interesting.
'I can place a dungeon!? However, the name catches my eye… "Great Tomb of Nazarick Floor 1" means I can summon and rebuild Nazarick? But what does "Floor 1?" mean? Can I only summon back one floor at a time?'
As Momonga attempted to register what had just happened, the dungeon collapsed. As the walls started to crumble, the roof started to crumble, opening a gaping hole in the walls. Momonga reacts quickly, jumping out of one of the holes. He finds himself suspended in the air and surrounded by an extensive grassland with large mountains surrounding the area and a large forest to his left.
"[Fly]," Momonga quickly cast fly, which allowed him to float and move around in the air.
He then looked behind him to see the dungeon start to disappear. As the floating island, he used to be on, started to reform back to what he thought was its original form.
'Interesting, so it seems that dungeons are built upon the environment, but when a dungeon is destroyed, the surrounding terrain returns to its original formation.'
Momonga starts to head toward the ground below him, not wanting to stay up in the sky for an extended period due to the vulnerabilities it left. However, he spots a few figures walking on the road towards him. He looks down upon them, trying to figure out what they look like. One of them is dressed in black and seems like a necromancer. The other was a petite cat girl that looked like a child wielding a sword, and the other was a gigantic wolf with black jet fur and looked similar to a dire wolf.
'Huh? Could they possibly be the adventurer? It seems they are heading in my direction. Could they have possibly planned to raid the dungeon I was just in?'