Author Notes: Hello! I'm Mikezilla. I've started writing this new story because I recently started reading the light novels for Reincarnated as a Sword. Currently on light novel 4, and it's quite a good read so far, so I decided to make a crossover between Overlord and Reincarnated as a Sword, I'm hoping it goes great!

Stay tuned for more chapters as I'm hoping to update this more often than my other stories although it still may take some time to write new chapters since I'm still reading the light novels for Reincarnated as a Sword.

Discord Invite: discord. gg/J7ekhYFbGh


Yggdrasil Dungeon Master

- Chapter 1 -

YGGDRASIL, a DMMO-RPG or, in other words, "Dive Massively Multiplayer Online Role-Playing Game," was a viral game in the year 2126 AD made by Japanese developers who were inspired by virtual reality and its unlimited possibilities. However, even though it was highly successful, all good things eventually ended as the servers eventually started to shut down. A player known as Momonga, the guild leader of Ainz Ooal Gown, was sitting in his throne room awaiting the countdown of the server.

He recently dabbled in an Npc's setting known as Albedo, an Npc created by a member named Tabula Smaragdina. However, Momonga seems to be more focused on the present and not on what he did to her settings. A slight sigh comes from Momonga's non-existent mouth, giving off a sense of acceptance. As he looks around the throne room from his seat, gazing at the flags of his friends that decorated the throne room's walls.

'What a fantastic time we've had. The work of art that we call the Tomb of Nazarick was outstanding. We even managed to defend it against the Union of Eight Guilds. The raid on us was massive, counting to an outstanding 1500 players, which we all stopped at the Eighth Floor Amphitheater. Even though YGGDRASIL is shutting down, I can't help but relapse on that memory.'

Momonga looks at his in-game hub. The in-built timer slowly counted up, meaning the servers were soon closing.

[23:59:35, 36, 37]

Momonga couldn't help but think of all the NPCs and structures he and his friends built together.

[23:59:48, 49, 50]

'I should most likely go to sleep once the servers have shut down. I wouldn't want to be late for work.'

[23:59:58, 59–]

'Thank You, my friends! I hope I'll see you in the real world someday.'

Momonga closed his virtual eyes awaiting the logged-out notification. However, what happened next was incredible and shocked him to his very core.

[0:00:00… 1, 2, 3]

'Huh!? The server didn't shut down!?'

Momonga instinctively opened his eyes to see himself in a strange new place. He looked down, expecting himself to be sitting upon the throne-room chair but instead, it was replaced with an old broken down stone chair. He immediately stood up, not knowing what to do, slightly starting to panic at this new situation he found himself in.

'What's going on!? Could I've been transported into a different game?'

As Momonga thought that, he started to breathe in with his bony nose. In-which smell started to flood his sense of smell, which was impossible in virtual reality games.

'HUH?! Smell? No, it's impossible, game developers have been trying to introduce senses like smell into a game for decades. Plus, virtual restrictions made it almost impossible to implement such a feature, fearing that people would confuse virtual reality for real-life.'

Momonga then noticed that he was still holding the Staff of Ainz Ooal Gown, which he promptly put into his inventory due to the present situation. Momonga then eventually noticed that the smell that was flooding his senses wasn't typical. Instead, it was a metallic smell and a massive stench as if something was rotting. This made him subconsciously move forward. Finally, he reached the source of the smell, even after a couple of steps, he came across a rotting humanoid body; he identified it as a human.

The body was ripped In-half like some creature had ravaged it for sport. Maggots, we're eating away at the dead human's rotting flesh. Momonga quickly noticed that this human was missing. Its arms and legs, meaning those were the limbs that went first. Which meant the human was left to bleed out at the creature's enjoyment.

'Well, this is a grim sight, but this bothers me a tiny bit as I'm not feeling any disgust towards this rotting corpse. I would've been throwing up or in a stressful, emotional state in real life.'

Momonga starts to look around a bit more, roaming around in the long hallways that occupy this structure. Though he's curious about a few things, his spells don't work as they used to in YGGDRASIL.

'It's a bit weird, but I can feel all my spells like a long mental list when I focus a tiny bit. I can also feel how much MP I have and how much HP I have. It feels so natural that it comes to mind immediately.'

Momonga experiments with his thought patterns, figuring out how to thoroughly utilize his entire arsenal of spells.

'Dark Wisdom still amazes me with how many spells it allowed me to learn. For example, in YGGDRASIL, I learned over 700 spells thanks to Dark Wisdom increasing my spell limit. It has come in handy in many cases, and right now is one of them as I have an entire arsenal I can pick through spells for any given situation.'

Momonga continues to move down the long winding hallways, finding it quite ridiculous how this place is structured.

'Could this possibly be some dungeon? Unfortunately, I haven't encountered any mobs yet, so I'm questioning myself here and there about that possibility. Still, it's becoming more prevalent over time.'

As Momonga concluded, he heard a bit of noise which he quickly moved towards, coming across an undead skeleton. However, it didn't seem all-to powerful and looked quite fragile.

'Huh? A skeleton? In YGGDRASIL, many skeletons were low-level mobs that could easily be defeated. Although I could use a skill such as [Create Low Tier Undead] to make them, it doesn't serve much purpose since they're too weak.'

The sound of bones can be heard as the skeleton turns to Momonga. They lock eye contact, and even though they lack eyes, the moment alone makes up for it. A few seconds pass by the skeleton and Momonga in a seemingly long staring contest when suddenly the skeleton starts to charge.

"[Magic Arrow]" Momonga said as an arrow made of magic flew out of his hand. It then pierces the skeleton's body as its bones shatter and fall to the ground.

That was particularly easy; I expected a bit more from that low-level skeleton since it didn't look all too brittle. It seems like it had similarities to its YGGDRASIL counterpart, but that's not to say all undead are like that. No matter, time to resume my exploration of this structure. Hopefully, I'll come across something intriguing.'

Momonga resumes his travels through the dungeon, eventually reaching a giant door that is decorated. The design is unique, and It seems that people are raising their hands to a "God," and their souls are being taken out of their bodies.

'Could this possibly be a God of Death? Hmm... I want to open this door, but I'm afraid something might be lurking behind it. It does look like a dungeon boss door; could it possibly be that? In YGGDRASIL, boss rooms weren't uncommon. It was the first warning signal for parties, although there were times when boss zones didn't have such obvious signals, and players would walk into their death. That is why it is best to be prepared or even over-prepared for those types of situations. It could happen at any time when exploring the worlds of YGGDRASIL. Even though I'm trapped in this structure, I will not just walk into a room out of sheer negligence. I'll prepare a bit first.'

Momonga starts to cast a few spells; it seems more buff than anything.

"[Lesser Strength], [False Data: Mana], [False Data: Life], [Resist Weakening], [Shield Wall], [Greater Magic seal], [Greater Teleportation]." Momonga casted these defensive spells in under a minute which was quite fast.

'I think that covers the basics, [Lesser Strength] Increases one's strength even if by a tiny bit. [False Data: Mana & False Data: Life] gives false data for MP and HP if [Mana Essence] or [Life Essence] is used. [Resist Weakening] is a spell that prevents someone from being weakened by an abnormal spell. And finally, [Shield Wall] creates an invisible shield around a target, which is me. Oh! And [Greater Magic Seal] combined with [Greater Teleportation] so that I can activate it in case I need a quick escape by saying [Greater Magic Seal: Release].'

Momonga moves his hand toward the door, ready to enter. But instead, the door opens independently, revealing the boss room, which was to Momonga's predictions and is why he took such precautions. Flashes of light start to bounce off the walls, and the crackle of fire can be heard as blue flamed torches light and illuminate a blue haze across the entire room. What stands in the middle is a gigantic skeleton knight, which Momonga almost mistook for a Death Knight, but this one is bigger.

'Alright then! Let's see what you can do!'

Momonga moves into the room, prepared for the battle to come. But right when his foot hits the floor, the gigantic skeleton moves immediately, summoning a skeleton war-horse alongside him.

"I guess I can presume you are a skeleton-knight then, let's see what you can handle. You will be my experiment! [Penetrate Magic: Acid Arrow]" As Momonga casts the spell, a green arrow fires out of his hand, hitting the skeleton knight. However, It doesn't seem to do much damage, which Momonga wasn't shocked about.

'So! It seems that it has some slight resistance to magic, though It is still nothing more than a brute guarding a room of no importance; even with its great size, this will be easy.'

Momonga gets his footing again, and he instantly starts a volley of spells.

"[Silence], [Shockwave], [Fireball]" Momonga cast three spells in a short amount of time. The first spell [Silence] was to eliminate all sounds in the area for some time. Next, [Shockwave] is an invisible wave through the air. It's said to be strong enough to crush plate mail. And finally [Fireball] a ball of flames fired directly toward the Skeleton Knight. It was meant to exploit the critical elemental weakness of the undead, which was Fire and Holy magic.

As the shockwave traveled toward the undead knight, It seemed to do nothing to it, indicating that it had more than just slight magical resistance. This was confirmed when Fireball hit the undead knight, which did practically nothing to it.

'Interesting, so it seems that I didn't give the undead knight enough credit. It has a more magical resistance than I first perceived. I'll assume its resistances are close to or comparable to the skeletal dragon, which is resistant to 6th tier magic and below, so I'll jump to 6th tier magic or above.

"Even though your magic resistance may keep you alive, your death is inevitable," Momonga said, awaiting the skeleton knight's next move. However, his words were met with a quick charge by the skeleton war-horse. But Momonga reacted in a quick haste attempting to divert the war-horse's path.

"[Dragon Lightning]" Momonga casts a lightning spell that forms a singular dragon that shoots into the skeleton war-horse. However, its resistance wasn't as strong as the skeleton knight, and it turned to dust instantly. Although this sent the skeleton knight into a pit of rage, it seemed that the skeleton knight was somehow boosted.

'What? A rage boost? Could it be that he might be part of a barbarian class?'

In an instant, the skeleton knight was upon Momonga. It slashed its sword with quick haste.

"[Greater Magic Seal: Release]," Momonga released his seal, which teleported him back, allowing him to dodge the incoming attack.

'Alright, I think this is enough experimenting; this fight is honestly starting to annoy me.'

"Time to end this... [Chain Dragon Lightning]," Momonga cast a spell which formed massive chains of lightning in his hand, which he shot forth. From it, a dragon formed, which quickly pierced the undead knight, destroying it entirely.

Momonga let out a slight sigh at his disappointment in that fight.

'Well... I did get good information out of that fight, at least. I can use my spells without limitations, although my mana consumption is still the same as in YGGDRASIL. Still, there are slight differences, such as me no longer having a user interface for the spells. But this brings up another matter; since there was a boss on this structure, the only obvious conclusion is that I was transported into a dungeon. If so, where could Nazarick have been transported? After I escape this place, my first few objectives would be testing out the Staff of Ainz Ooal Gown, then searching for the Great Tomb of Nazarick.'

Momonga started to walk around a bit more, exploring the boss room he had just conquered. He eventually noticed that the skeleton knight and skeleton war-hose both dropped what seemed to be a crystal. He picked both crystals up and opened a luminescent purple portal. He then stashed both crystals inside, storing them deep in his inventory for later research purposes as he saw them as monster drops.

'Well, I can presume that the crystals are monster drops. So there are still some game mechanics from YGGDRASIL or any other basic MMORPG. Hopefully, this will become useful at a later date.'

Momonga stored this information deep in his mind, keeping a mental note. Then, he looked around a bit more and spotted a newly opened door; he quickly headed toward it. Peeking his head through, he looked to the right and left. Looking to the right, he saw a dead end. Although he saw a long hallway to the left, he logically took that one.

Momonga's footsteps make an ongoing sound down the dark hallway and quickly pass by, taking twenty minutes. This makes him a bit wary since it's been eerily silent since he's left the boss room. He hasn't even come across the occasional low-level skeleton. Even though it makes him a bit wary, he's pretty calm. However, that might be because of his undead nature and that he still has his buff spells activated, which he cast before the boss room. Plus, he can sense undead naturally so that they wouldn't get a jump on him.

A few more minutes pass as he travels down this hallway, and he starts to hear a noise. As it seems a massive hoard of monsters grows ever-so-closer, he starts to count them fifty? A hundred? After a few moments, he realized that it was impossible to count them all at this moment.

'That's a lot of monsters, and this must mean that there's another boss, meaning the previous one was a mini-boss which makes more sense because of the mini-bosses weak nature. However, I don't want to deal with these monsters, so I'll have to end this quickly, and I know just the spell.'

"[Maximize Magic: Thunderball]," Momonga said as a gigantic thunderball formed in his hands. He pointed it towards the incoming horde. As he let go of the thunderball, it flew with great speed. It caused the monsters to scream in pain as it collided, and half of them turned into dust. The other half had multiple body parts burned to a crisp as they lay down in defeat and later died from the injuries.

Momonga walked past the dead horde, picking up their crystals, which he stored deep in his inventory. He immensely enjoyed gaining new items, hinting toward his collector's instinct. However, after a few minutes passed, he decided to resume his travels through the hallways. He eventually came across another door. It had a similar design to the last door, but this time around, he was prepared, so he immediately reached toward the door. In which it started to open by itself. He noticed this and waited for it to open once it did, he walked through, leading him into another large circular room.

'Another boss room, perhaps?'

Although, right when Momonga thought it was a boss room, a noise in the corner of the room confirmed it.

"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 adventure? It seems they are heading in my direction. Could they have possibly planned to raid the dungeon I was just in?'