The Twilight Void, a region found in the galaxy's Unknown Regions, existed in space. By 27 BBY, the sentient Chiss and Yuuzhan Vong species's military groups clashed there, leading to a battle where the Chiss achieved victory. The 55 ABY publication Mitth'raw'nuruodo Reconsidered: A Patriot's Perspective featured Lenang O'Pali's reference to this Twilight Void engagement.
Jason Fry and Paul R. Urquhart's The Essential Guide to Warfare, a 2012 reference book, initially mentioned the Twilight Void. The StarWars.com Online Companion for the 2009 reference book The Essential Atlas situated it in grid square D-7.