Operation Gehenna

Operation Gehenna was a campaign of Demiurge to allow Nazarick to place a foothold in the New World.

Background
After the Great Tomb of Nazarick has somehow been transported to the New World, Momonga and Demiurge went together outside to investigate. Ainz Ooal Gown (known as Momon at the time) and Demiurge were amazed by the beauty of this world and the two pondered if they may have some sort of purpose for being here. At that moment, Ainz lightheartedly mused that the reason could be for them to take over.

Although that was merely a joke by Ainz, Demiurge took his words as literal. Following the day when Momonga rechristened himself as Ainz Ooal Gown, Demiurge informed the denizens of Nazarick on what their king has told him. Everyone gladly accepted it and swore to make Ainz Ooal Gown's dream a reality.

Much time has passed, Ainz Ooal Gown and Narberal Gamma had travelled to the New World and posed as Momon and Nabe of the Adventurer team, Darkness. They had built a phenomenal reputation, earning the respect of this world's inhabitants. Meanwhile, Demiurge has concocted a plan to further reach that goal and chose the Re-Estize Kingdom as the perfect tool.

Tsuare Rescue Mission
Sebas Tian and Solution Epsilon had been living in the capital, acting as spies for Ainz and were working undercover to gather information. During that time, Sebas discovered a young slave girl named Tuareninya Veyron and took her in. This drew the attention of Eight Fingers and after a series of events which led to the capture of their subordinates, the organization decided to kidnap the Tuareninya to lure Sebas out to be killed for his defiance against them. Ironically, their latest scheme proved to be defiance against Sebas's master, Ainz Ooal Gown who commanded his Floor Guardians to hunt the criminals down like the animals they were. Sebas was joined alongside another party who also were also determine to bring Eight Finger down. The party comprised of Brain Unglaus, Climb and Lockmeier. Together, they confronted Eight Finger's security forces, Six Arms. Sebas single handedly killed five of them while Climb managed to defeat the remaining one. The team successfully rescued Tuareninya and crippled the criminal organization.

Demonic Disturbance
Meanwhile, Mare and Entoma had just assaulted the mansion of Hilda, one of the high ranking leaders of Eight Fingers. After killing all of the guards, they captured Hilda who was taken back to Nazarick by Mare while Entome stayed behind to finish off what remain.