N-K Necrosis was a highly advanced combat droid created from the body of the late General Grievous of the Confederacy of Independent Systems during the Galactic Civil War. Doctor Nycolai Kinesworthy, a cybernetic scientist, was hired by the Galactic Empire to create the Necrosis droid. Dubbing the project "N-K," Kinesworthy established a shop in the Myyydril Caverns on the planet Kashyyyk to begin work on the droid. He eventually hired the scientist Treun Lorn to help advance the project. After Lorn hired the assassin droid IG-72 to retrieve a pair of outdated IG-100 MagnaGuards to serve as N-K's bodyguards, the dark side Prophetess Merili led the two scientists to one of Emperor Palpatine's secret storehouses on Utapau, where she provided them with the mechanical body of the cyborg Grievo