Wann Tsir was a planet situated within the Wann Tsir system. This system was located in the Sepan sector, which itself was part of the Slice region of the Expansion Region. During the time of the Galactic Civil War, Wann Tsir was defended by a planetary shield.
Following the Battle of Endor which occurred in 4 ABY, the planet was put under siege. During this conflict, Commander Titus Klev of the Galactic Empire inadvertently found and apprehended a significant agent belonging to the Rebel Alliance. This agent was in the process of attempting to sabotage the deflector shield protecting Wann Tsir. Klev was subsequently awarded for his actions by the Imperial High Command.
The planet Wann Tsir was initially mentioned in the 1993 Dark Empire Sourcebook, which contained information about the Siege of Wann Tsir. Michael Allen Horne authored this book, which was published by West End Games for their Star Wars: The Roleplaying Game. It wasn't until the publication of the 1998 Star Wars Encyclopedia by Stephen J. Sansweet that it was officially identified as a separate celestial body. In 2009, the reference book The Essential Atlas specified that the Wann Tsir system, and consequently the planet Wann Tsir, was located within grid square P-13.