The Occlusion Zone, which has also been referred to as the Exclusion Zone, Free Sectors, Liberated Worlds, Nihil space, or Nihil territory, and is sometimes shortened to O. Z., encompassed a region of space consisting of ten sectors. This area was situated in the Galactic Frontier within the Outer Rim Territories. The Nihil asserted their claim over it and isolated it using a barricade known as the Stormwall in 230 BBY. As a reaction to the Jedi Order's and Galactic Republic's attack on the Stormwall in 228 BBY, Marchion Ro of the Eye of the Nihil orchestrated an expansion of the Occlusion Zone. This expansion resulted in the absorption of additional Republic territory, including two entire sectors, multiple systems and planets, and the division of the Seswenna sector just before reaching Eriadu. After the escape of Jedi Master Avar Kriss from the Occlusion Zone, Ro repeatedly expanded the Stormwall, seemingly without any discernible pattern from the perspective of the Republic and the Jedi. Ultimately, the Occlusion Zone grew to encompass a significant portion of the Chommell sector in the Mid Rim, including the planet Naboo.