(Disclaimer 1: I do not own Warhammer 40,000. Warhammer 40,000 is owned by Games Workshop)

(Disclaimer 2: I do not own Overlord. Overlord is owned by Kugane Maruyama)

(I finally got Grammerly on my computer and I added 5 more Past Dwellers but you'll meet them later in the story. I attempted to try and change the prologue a bit to try and make it not too cringey. I've been trying to fix the typos all day! I usually write with a text-to-speech device on my computer. Unfortunately, I wrote a majority of this on my phone.)

I'm actually really nervous that this might suck.

I also intend to do a lot of browsing on the Overlord Wikipedia since I don't think I'd have time to read all the volumes of the Light Novel, unfortunately. I started writing this while on a cruise to Mexico. It's a pain in the ass trying use the app while in Airplane Mode! But on a positive note, recently got seasons 1 and 2 of Overlord. I'm thinking about getting the LN equivalents to season 3 and the Light novel volumes that take place after that.

Can anyone guess the grunge song quoted in the prologue of this pitiful attempt at a 40k/Overlord crossover?

Welp...here goes nothing...

*winces as he prepares to get torn a new one in the comments/review section*

Prologue: true prophecy is true, brah…

"Messenger of fear in sight

Dark deception kills the light

Hybrid children watch the sea

Pray for father roaming free"

-The Thing That Should Not Be by Metallica

It was something that Johan Richter and his friends always remembered and WOULD remember for the rest of their existence...

He and 20 others were HUGE fans of 6 things: grunge, heavy Metal, military history, hentai, Overlord and Warhammer 40,000 (specifically Chaos). They all played the 40k tabletop RPG Black Crusade. Johan was the GM. They had it to where their characters created an alliance of warbands that claimed to rule over the Screaming Vortex. This sub-faction was known as the Unity of the Vortex temporarily led by Malich, a Chaos Space Marine character quoted in the game's main rulebook. They loved the story they all set up.

Suddenly, they all awoke on the fictitious planet that was the Vortex's base of operations! They were stuck in the Warhammer 40,000 universe! But...all 21 of them saw everything in anime form. They all found this weird at first, sure... but eventually, they had all gotten used to it and gave up on trying to figure out why. What shocked them was that the characters they created claimed that all 21 of them were seen in visions the characters had been having. They joined their characters' respective warbands and became the Past Dwellers.

Unfortunately only Johan Richter (Now known as Lord Enforcer Valek) and Kevin Martinson (Now known as Aspiring Champion Ketarus) had managed to remain at least "mostly" sane while the other 19 Past Dwellers were driven to utter madness.

Nordo, who was part of the chaos corrupted genestealer cult called the Brood Monks Brotherhood had it the worst. It didn't help with what they discovered about their new surroundings. It happened a year ago. Somehow, A red marker from Dead Space and five battalions of Unitologist Militia soldiers ended up in the 40k universe! The Brood Monks accidentally encountered the Unitologist troops. Then the necromorphs popped up. The marker drove Nordo even more insane, but long story short they managed to destroy both the marker and the necromorphs and the surviving Unitologists became worshippers of Nurgle and joined the brotherhood. However, the extra damage had already been done to Nordo's sanity. Valek was glad that at least both the marker and necromorphs that teleported into the 40k universe were no more.

Valek and the five other past Dwellers in the Traitor Guard all met on the "bridge" of the Space Hulk, DX 38 (damn the Unity really needed to change the name of its Flagship!) which was orbiting the feudal world known as Yggdrasil Prime.

"Kinda reminds me of Overlord. What the frak is so warp damn strategically important about this planet, anyway?" complained Xarian, the past Dweller of the True Emperor's Liberation Front who spoke with a Polish accent. He wore a defiled Adeptus Abities uniform. "I mean aren't we supposed to be kicking Xenos ass and killing Loyalist sukas on Vigilus? Why'd we leave? What the hell, man? And why did the boss only call the Chaos Renegade Militias instead of calling ALL the warbands? What the hell's going on?"

{ Author's Note: I assume 'sukas' means 'bitches' in both Polish and Russian. Please correct me if I'm wrong and I will correct it. English is my native language and I know only a little Spanish from Spanish class in high school and a little Polish from a visit to Poland}

Valek rolled his eyes. "Look. The Dark Captain and I will explain everything. Just shut up and be patient."

Xarian sighed in annoyance. "Alright fine."

A space marine stepped out of the shadows. His face was burnt and scared from centuries of combat experience. His teeth were practically fangs. He spoke in a raspy voice. "As you are all well aware, I, Malich Despairion, cannot lead the Unity on my own. I've decided to step down and simply remain as the Dark Captain of the Burning Eye Legion. Someone else should take up the role of Master of the Screaming Vortex."

Everyone except Valek, the Burning Eyes and the Holy Oath were shocked.

One renegade could be heard shouting: "The Prophecy foretold by the Black Legion's Lord Vigilator is happening already!? By the Dark Gods. This was unexpected."

Another Renegade was quick to respond. "Oh, grow the frak up, Simmons. The Prophet is a warp-damn myth created by desperate optimism!"

Malich raised a gauntleted hand and the crowd of guerrilla soldiers and space pirates went silent. "Fear not, for our new Commander calls Yggdrasil Prime his home. Yes, my brothers and sisters, the prophecy is true. There are 9 nation-states on Yggdrasil Prime that have caught our attention. They are: the Sorcerous Kingdom of Nazarick..."

The renegade past Dwellers aside from Valek: Dakkelen of the Holy Oath, Aganar of the Skull Hunters Combat Regiment, Osarius of the Free Systems Coalition, Nordo of the Brood Monks Brotherhood, and Xarian of the True Emperor's Liberation Front all stood in confused shock as Malich continued and a holographic map of the planet appeared.

"...The Re-Estize Kingdom, the Baharuth Empire, the Elf Kingdom, the Roble Holy Kingdom, the Slane Theocracy..."

NANI!?

Those were nations from Overlord! So THAT'S why they saw everything in anime form! Holy shit! 40k had come to the New World! Malich had listed the seventh nation-state.

"...the O'Shar Republic..."

Wait. Who in the fuck are the O'Shar Republic?!

"...the Sakarian Principality..."

Who in the frak are the Sakarian Principality?!

"...and finally, the latest nation-state to be founded ...the Royal Empire of Jakora."

Who in the frakking FUCK are the Royal Empi- ...screw it! You get the idea!

A Renegade from the True Emperor's Liberation Front spoke up. "What do we know of these factions?"

Malich smiled. "I'm glad you asked. You have our spies, Valek and the other Past Dwellers to thank for that information. I'll have the Lord Enforcer explain. Valek?"

The spies of the Unity had their origins in cults linked to the Alpha Legion, so they were extremely skilled and were reliable sources of information.

Valek cleared his throat.

"After spying on these nation-states since Nazarick's mysterious appearance on Yggdrasil Prime, we have recently discovered that an Inquisitorial retinue has infiltrated the Slane Theocracy. This explains their unofficial nation-wide conversion to the Imperial Cult about a month ago and the suspicious deaths of its leaders, the Cardinals. The Slane Theocracy has become a puppet government of the Imperial Loyalists and their False Emperor, therefore they are one of our foes. As a result of this, the Slane Theocracy's deadliest warrior, Zesshi Zetsumei has defected to the Sorcerer Kingdom."

"I FRAKING HATE THOSE INQUISITORIAL SHITWADS!" shouted Nordo, the past Dweller of Nurgle. He wore a Mordian Iron Guard uniform that looked similar to a 21st century enlisted USMC dress blues uniform, the coat had Marker symbols all over it and the original iconography replaced with chaos iconography. He was also wearing black combat boots.

"So, the Corpse-worshipin' scum are copying a strategy from the 'Nids, eh?" muttered the Vagabond who was the Chaos Kelermorph of the Brood Monks Brotherhood and one of Nordo's mentors. "Nurgle above, the Loyalists must be getting desperate."

Valek nodded. "To top it off:

the Re-Estize Kingdom has been in infiltrated by the Tyranid Genestealer Cult known as the Regiment of the Clawed Hand,

the Elf Kingdom is siding with the Ynari in exchange for the Ynari homunculi to turn the Elf king into an Eldar,

plus, the O'Shar Republic...(formerly known as the Argland State Council) is secretly allied with the Tau Empire after the scum preached their 'Greater Good' crap to the local populace,

and an Ork Clan of Mork has established a hidden base somewhere in the swamps of Yggdrasil Prime...not to mention the Greenskin bastards have brought Feral Ork tribes with them. They have completely destroyed the abhuman race known as 'Orcs' with a 'c'"

Aganar who was an American of Mexican ancestry groaned as he facepalmed. He wore apparel akin to those knife wielding enemies from Spec Ops: The Line and was wearing a Green Beret with a Khornate symbol on it. "So that means that the Coños will have feral world allies to act as swarmer units and magic Casters to supplement their psykers?"

{ Author's Note: I heard 'Coños' means 'Cunts' in Spanish. Please correct me if I'm wrong and I will correct it. English is my native language and I know only a little Spanish and a little polish}

"I'm afraid so, Aganar." Dakkelen raised his hand and Valek pointed "Yes, Dakkelen?"

"Uhhh...I'm curious, Lord Enforcer Valek...What's the political situation with the Principality and the Royal Empire?"

A somewhat sadistic grin crept its way onto the Traitor Commissar's face behind the bandanna he was wearing. Valek chuckled as he answered his fellow Past Dweller's question.

"You savages are gonna LOVE the good news I've got for you...completely untouched by any Xenos or heathen influences...no knowledge of the galaxy at large...and they are so despised by their OWN people who live under oppressive absolute monarchies that they would be more than happy to rebel against their oppressors. Perfect targets for sick monsters like us."

The bloodthirsty cheer throughout the briefing room could probably be enough to wake the dead. (pun intended)

When the Renegades managed to contain their excitement, Valek continued.

"And before you ask...The Baharuth Empire is a vassal state of Nazarick and the Holy Kingdom seems to be on the verge of defeat...although remnants of the Roble Holy Kingdom's military have established a resistance movement, The so-called 'Holy Kingdom Liberation Army'...in my opinion... the pricks are just a buncha weak, pretentious, arrogant, self-righteous, holier-than-thou, heathen domkofts. They are led by a woman named Remedios...pfft...more like 'Retardios' if you ask me."

Some of the renegades chuckled at the politically incorrect insult. There was a short pause as Valek was lost in thought. "Sir?" A concern Brood Monk asked. "Is something wrong?" Valek regained his composure. "No, there's nothing wrong." He cleared his throat and gestured to the other Past Dwellers. "..Uhh...if you'll excuse me I must converse with my kin." The Traitor Guard and Malich gave The Past Dwellers weird looks but let it slide as Valek, Dakkelen, Aganar, Osarius, Nordo, and Xarian all ran into a separate room.

"Oh my fucking god, lads! we just might experience an Overlord/ Warhammer 40k crossover!" Dakkelen shouted with fanboyish excitement.

Aganar was sweating. "Dude, are you sure we wanna drag Ainz into this? Keep in mind that he is ALSO trying to maintain a 'badass cunning dark fantasy antihero' archetype...just like the 6 of us and the other 15 Past Dwellers back home in the Vortex. I haven't been this nervous since my family first moved to Stockton from Fresno."

Nordo nodded. "Dude's emotion suppressor thingy would be struggling to keep him from freaking out if he ended up with 5 armies groveling at him."

"Yeah." Osarius said. "Not to mention that the NPCs, the people of Nazarick, Niea's cult and the chaos would all be expecting him to fight and win a planetwide futuristic war on 5 fronts. I thought that Khayon made that 'Prophet' shit up to when a bet against Valek"

"He DID make it up." Valek said in reassurance. "Aside from us, he and the rest of the Ezekarion are the only ones who know that the "prophecy" is bullshit. Besides, he always maintained that prophecy is a load of superstitious horseshit. At least it convinced the Unity to get off their asses. All it took was to tell them that going to Vigilus and killing as many heathens and aliens as possible would cause a savior to lead them to glory and blah blah blah."

Dakkelen shrugged. "Something tells me the denizens of Nazarick may be put off by all the chaotically chaotic chaos-y chaos-ness and shit."

Xarian piped in. "Look, We need leaders, they'll need the tech. Chaos works with Nazarick because...prophecy. Nazarick works with chaos because...useful army of psychopaths from space. we work with Chaos because good is dumb annnnd we work with Nazarick because...Albedo, Nigredo, Rubedo, The Battle-maids, Shalltear, Zesshi, EvilEye, Hell...even Clementine are all hot and gorgeous as fuck!... My mind says: 'forget it. It ain't gonna work.' But my third leg says: 'your favorite OP waifus would probably be awesome dominatrixes, man! It's totally worth a try!'"

Nordo made a grin. "Yeah...I'd LOVE to submissively make out with all of them and be their bitch! Anime chicks always look sexier when they are NOT wearing lipstick...lipstick on anime chicks is kind of a turn off for me...even if we probably wouldn't be allowed to touch...we can still gwak like a bunch of weeb perverts, right?"

Valek nodded immediately. "Ja, I agree with Xarian's crotch...Overlord waifus are best waifus...it's a weeaboo's wet dream. Nazarick plus Chaos = super duper sexy awesome sauce, therefore Old Bone Daddy is the Prophet of the Unity. Time to make Ainz Ooal Gown the Overlord of the Screaming Vortex...whether he likes it or not...I'll just say that some BS that the Supreme Beings are demi-Gods of the Dark Gods or something, hopefully, our fellow heretics are gullible enough to believe it (no offense against the warlords and their subordinates who taught us everything we know) Also we've gotta come clean with Ainz but NOT when ANYONE other than us Past Dwellers and him are around. And NO ONE says anything about Overlord being a light novel or an anime. Ainz can only know about 40k being a fictional universe, not Overlord. Got it?"

the Past Dwellers all returned to the briefing room. Valek continued.

"Now then ladies and gentlemen you're all probably wondering what has drawn the Unity's attention to this world. You remember the prophecy that Lord Malich mentioned, correct? That's because Nazarick's leader will lead us to victory. This man... "

The map of Yggdrasil Prime changed to an image of what looked like a walking skeleton. Except this skeleton's height reminded the Renegades of a space marine's height. He wore what looked like a ceremonial robe of some sort. He had red glowing eyes and carried a staff made of skilled craftsmanship.

"He is the Prophet sent to us by the Dark Gods! His armies are led by holy daemonic beings created by Demi-Gods from the warp! He is Ainz Ooal Gown! He is our Overlord!"

The Traitor Guard began a chant which echoed throughout the ship:

"AINZ OOAL GOWN!"

"AINZ OOAL GOWN!"

"AINZ OOAL GOWN!"

"The Sakarian Principality is our first target. Dealing with them should take about a month. After the Prophet takes notice of our courageous deed, we shall reveal ourselves to him, but when we do so...we are going to do it with style! We'll discuss the assault on Sakaria in one Terran standard hour. Let our Black Crusade begin!"

One year later*

"Wait...What exactly you mean the Principality is 'more or less destroyed'? And by whom?" Two years ago, Ainz Ooal Gown had promised to destroy the Sakarian Principality after it's soldiers massacred several villages that were under Nazarick's protection. He knew that Sakaria had suddenly gone all 21st century North Korea on the New World's ass for a whole year, but he never thought that this was the reason why. Albedo was afraid Ainz would be angry with her. The Sorcerer King noticed her reaction. "I'm not mad, Albedo. I just wasn't expecting this to be the case."

"Demiurge and a small force are surveying the damage as we speak, Lord. He feels that you should see this for yourself." The succubus reported.

"I see...I will be there shortly. I need you to keep an eye on Nazarick while I'm away."

Ainz collected his staff, stood in the center of the room and uttered one simple incantation.

[Gate]

A portal appeared before the ruler of death and he stepped through it.

When Ainz reached his destination which was a hill overlooking the capital city of the Sakarian Principality, he saw Demiurge looking down at the city...or at least...what was left of it. "What do you think exactly happened, Demiurge?" Ainz asked the Arch-Devil. Nazarick's strategist appeared to be just as surprised by the situation as everyone else. "Well, my lord..." he said. "It seems someone got here first...this explains the Principality's silence and inactivity." Ainz and Demiurge noticed certain details. But those details only led to more questions than answers. And one of the questions that Ainz had was...

What the fuck!? Are those tank tracks!?

A week later Ainz couldn't shake the nervousness and confusion in his mind as he sat at his desk staring at the papers detailing the fate of the Principality.

Another thing that bothered him was that while he and Demiurge inspected the ruins of the Sakarian palace, he saw the words:

"Glory to the Prophet of the Dark Gods" written in blood above the entrance.

As they went inside, the following was also written in blood:

I believe them bones are me

Some say we're born into the grave

I feel so alone

Gonna end up a big ole pile a them bones.

Whoever did this sure loved writing stuff in blood.

Later Ainz was in his office dwelling on the fate of Sakaria.

Man, this doesn't make any freaking sense! Ainz thought to himself Tank tracks! Fucking tank tracks! I mean what the hell is this, Gate: thus the JSDF Fought There!?

Albedo suddenly entered the room. "Lord Ainz, The lower lifeforms from the inferior nation of Jakora are launching an attack on the great tomb."

Suddenly explosions could be heard from outside the tomb. Ainz and the NPCs all gathered outside to see the Jakorans either dying or dead. Ainz could see in the distance several figures approaching the tomb. He realized that the massacre had been caused by artillery. The figures all stood in front of the tomb. We are so fucked... Ainz thought. suddenly they bend the knees. One dressed as something akin to a satanic version of a ww2 era Soviet commissar smiled and spoke with a German accent.

"Do you see brothers and sisters!? Behold! the Prophet Ainz Ooal Gown and the Holy daemonic angels created by the children of the Dark Gods stand before us as prophesied by the Black Legion's first Sorcerer! The Ruinous Powers themselves have given us our saviors! Be honored, soldiers of the Forces of Chaos, For we stand in the presence of the Unity's new Commanders! the Holy Land of Nazarick is now a place we protect with our very lives in return for the hope he has given to both the Unity and to the True Emperor of Mankind!"

The army behind him cheered and began waving flags...some of those flags were that of Nazarick.

WHAAAAAAT THE FUUUCK!? Who the- What the- How the-...What the HELL is going on?!

The man's excited grin only grew wider as Albedo stepped forward. "Who are you?" She asked sternly. The man chuckled. "Infinite apologies, Lady Albedo. Forgive this lowly human dog for his lack of manners. I am Lord Enforcer Valek...Our armies asked only to kill your foes in your divine eldritch names..." He bowed in a gentlemanly fashion. "For to kill in your names is to kill in name of our Warmaster Abbadon the Despoiler and to kill in his name is to kill in the name of your grandparents...the Dark Gods."

Demiurge adjusted his glasses with a smirk. "As expected of Lord Ainz. His plans continue to astonish and shame my highest expectations."

Ainz could only utter a single sentence in his mind:

Why me?

He looked at Valek who winked at him and the NPCs and whispered to where only ainz could hear him: "Look, Satoru or whatever your real name is...just play along, you boneheaded couch potato...just play along goddamn it...and tell the NPCs to play along too."

He...knows who I really am!?

"This calls for a celebratory sacrifice!" Valek suddenly shouted with glee. "Bring forth those two Sakarian maggots who refused the cause and the deserter." Two men were dragged in front of Ainz by two soldiers. the two captives were made to stand a in front of Valek in a single file line facing away from. A guy was a flamethrower set the first two captives (the deserter and one of the Sakarians) on fire. They died within at least two minutes. Valek then pulled out a combat knife and slit the throat of the deserter making the blood squirting from his wound extinguishing the burning body of the other two victims.

Whelp, at least we get some extra undead…..Let's a Death Knight and… Ainz decided to put some of the corpses of the Royal Empire's troops to good use as Skeleton Warriors "uh…Soldiers. Bring me nine of those Jakoran bodies." The Renegades did so immediately. Ainz transformed the Unburnt Sakarian's body into a Death Knight. But when he used the spell to create Skeleton Warriors, only ten corpses transformed. The chaos deserter's charred husk remained just that: a lifeless scorched body. Ainz also noticed that the ten skeletons looked different….their outfits looked more vampire-ish? Valek then said: "Grave Guard from Warhammer Fantasy?!"

*Ainz throne room*

"So you use this vague prophecy to put me in command of this sub-faction of yours? And you guys are also trapped in a game as well?"

"Yes, my Japanese friend. " Valek said with shrug. "Us and 15 others were 'isekai-ed' into a dark science fantasy franchise called Warhammer 40,000. The 21 of us are the REAL creators of the Unity of the Vortex. Turns out Abbadon doesn't give a flying fuck about the Unity, but we 'Past Dwellers' always manage to bullshit that it's all for him and the Gods." The Lord Enforcer smirked

"And In return for using the Baharuth Empire to provide a recruitment source for your Militias and playing the part of your 'Prophet'?..." Even though he couldn't show it. Ainz was skeptical. But what choice did he have?

"We keep both our true identities and your identity as a secret from your subordinates, we teach your NPCs how to tactically survive the 42nd millennium, and Yggdrasil-prime no go boom boom." Xarian answered

"Pleasure doing business with you, Mr. Japanese bone daddy man." Nordo said mockingly. "Just give us something to kill, and give the 6 of us opportunities to act like retarded fanboys when we think no ones looking and our militias will blow up the annoying things...'boss'". The word boss was dripping with sarcasm.

Great...now I have to live up to the expectations of freakin' space Satanists! Ainz lamented internally. Well, at least I have someone who knows what I'm going through...Well sort of.