Nazarick shows up in warhammer world in 2400IC after a hypothetical end of Overlord.

Ainz Ooal Gown has come to the New world but he isn’t alone. A close friend of his has also arrived in the New World. Except he wasn’t playing YGGDRASIL, he was playing a DMMO-RPG where there is no peace among the stars. Only an eternity of carnage and slaughter and the laughter of thirsting gods. Oh yeah, also this freaky motherfucker got four arms. LMAO.

What happens when Ainz Ooal Gown meets with he world of Warhammer fantasy and what would his adventures would be with the Men of the Empire and their allies and the ruinous powers to our bois Greenskins.

During the End Times, a group of survivors fled to another new world the surviving gods managed to make but it's heavily implied they didn't make it or is it? Because that new world they fled to is…well the New World. Now, Ainz Ooal Gown has appeared in the New World which is now the Ninth Realm, and is now in contact with the Mortal Realms. Adopted it from GhazzgullThrakan.

The Emperor lost, Humanity surrounded by enemies was decimated. Still, the flames of hope didn't die, something gave him a chance, a chance to start over, a chance to make right out of all the mistakes he'd made. A new universe, same objective. The light must prevail and humanity shall triumph. The Avatar of Order has arrived in the new world and it shall tremble under his feet.

My ideas

A lost Captain. His Last stand made and his Brother killed to a man. Himself Curiously alive he appears in a village, with little recollection of his last moments. The Weight of a lie he as told everyone on his shoulders, one even his brothers in the Lamenters Chapter did not know.

100 Years after the first advent, Ainz rules the world from his capital seat of Nazarick. However, instead of a new player being added to the fray, the sky's shift and change, as the planet had been torn through warpspace and time into the grim dark of the 40k galaxy.

6 dorks from the real world who are fans of both Overlord and 40k ended up trapped in the 40k universe after playing the Black crusade rpg. Then they found that the new world is a Feral world. Ainz finally found someone whom he can relate to... even if they’re all a little crazy. (DISCONTINUED)

Warp storms engulf the new world. Even Nazarick can feel this chaotic power. What will the overlord of Nazarick do after arriving to a place where the only future is endless war? one grimdark future where peace is just a dream.

Instead of the "New World" The tomb of Nazarick appear in the "Old World"

Es el cuadragésimo primer milenio, en una galaxia hostil las razas conquistadas hace milenios por Ainz Ooal Gown en la sagrada Terra ahora intentan sobrevivir a un universo despiadado que solo busca destruir el imperio que el dios overlord ha creado. En el siniestro futuro lejano, solo hay guerra.