The Samarkh Worlds, also known as the Samork worlds, is a sector-sized group of systems to the galactic northeast of the Vigo Sector; Once a major part of the Uthor Sector(primarily the Samarkh subsector, for which they are named) the Samarkh Worlds are now, one and all infested with Orks, who often band together and launch a Waaaghs! Into the nearby Vigo Sector.
the Uthor sector was one of the last sectors liberated in the Great Cruusade, and was largely passed by by traitor forces in the Horus heresy.
The sector was plagued by Ork Waaaghs! throughout its history, mounting in strength and scale throughout the 39th and 40th Millenia until fabled Ork Warlord Gutter Gorzhrag overwhelmed the Imperial defenders in 635.M40 and conquered most of the sector before dying from a rabid duck attack; the remaining worlds in the Malakai and Dubrovik subsectors were absorbed into nearby Vigo Sector.
Over the following hundreds of years, Malakai suffered constant attacks by Ork pirates, and even occasional Waaaghs! but the defenders were usually able to see these off with little trouble, but no Imperial effort to retake the Samarkh worlds was successful, and many people began referring to them as the 'Sam-Ork'Worlds.
The Final Waaagh!
In 996.M41, Azhrag the Slaughterer gathered a Waaagh! and invaded Malakai, easily overwhelming the defenders, weakened by the attacks of Toran the Murderer, and conquered the entire subsector except for the Squat refugee world of Ordo-Maghai.
Impatiently pressing on into the Dubrovik and Dorsai subsectors, Azhrag met no real opposition, but turned back to attack Ordo-Maghai again after the Squats destroyed the force he left to occupy the world.
While he was so occupied, Jan Skrsztuszki was sent, with a small fleet and an army composed mostly of mutants and Abhumans to defend the single Warp route from Dubrovik to Dorsai; ignoring his orders, Skrsztuszki invaded Dubrovik, and in retook the subsector in a series of hard-fought battles, finally meeting Azhrag in battle on Generes III; the enormous Skrsztuszki easily defeated Azhrag in close combat, throwing his Waaagh! into chaos, easily mopped up by Imperial forces.
Imperial operations in Samarkh