Alzar, the homeworld of the Alzarian people, existed as a planet within the Thanium sector of the Outer Rim Territories. A tragic event, the Stenax Massacres, devastated this world in 4 ABY.
At the dawn of the Galactic Republic, Alzar was discovered, only to be forgotten briefly before Human colonists settled it during the Tionese War. The native Alzarians, governed by a monarchy, welcomed these colonists, coexisting peacefully for millennia. During the Jedi Civil War, the Empire of Darth Revan controlled it, as did the Mandalorian forces before that. Eventually, following the defeat of the Brotherhood of Darkness in the New Sith Wars, Alzar became part of the Republic.
The Alzarians could not escape conflict, finding themselves caught in the Confederacy of Independent Systems' war against the Republic in 22 BBY, remaining under Separatist control until the CIS defeat in 19 BBY. Subsequently, the Galactic Empire incorporated Alzar into its domain. During Imperial rule, King Gokus acquired a pair of droids, who would later be instrumental in the Empire's downfall. These droids, C-3PO and R2-D2, aided the King in rescuing his abducted child, Prince Plooz.
After the death of Emperor Palpatine, the savage Stenax invaded Alzar and massacred the native Alzarian population. After these attacks, the remaining Alzarians lived under the control of Warlord Zsinj, who seized the planet to expand his empire. Following Zsinj's defeat, Alzar, like many worlds in the Borderland Regions, maintained neutrality during the New Republic's era. During the Yuuzhan Vong War, when the rest of the sector was invaded, the planet was isolated from the rest of the galaxy, forced to defend itself against the Yuuzhan Vong invaders. By 137 ABY, Alzar was located within Darth Krayt's Galactic Empire.
The planet of Alzar first appeared in the fourth issue of the Star Wars Droids comic book series, which was released in 1986. It was later mentioned in The Essential Atlas.