Malastare, a planet abundant in forested regions, was situated within the Malastare system in the Mid Rim, along the route of the Hydian Way. Its depths contained significant quantities of Malastarian fuel, a fuel of toxic nature exclusively found there. While the Dug species considered it their homeworld, the Gran species, who had established a colony on Malastare, represented it in the Galactic Senate. During the Invasion of Naboo, Ainlee Teem, the senator for Malastare, received a nomination in the election for the position of Supreme Chancellor. During the Clone Wars, a battle unfolded on Malastare between the Galactic Republic and the Confederacy of Independent Systems for control of the planet's fuel resources. This conflict resulted in the awakening of the Zillo Beast, a creature which the Republic successfully subdued, leading the Dug Council to ratify a treaty with the Republic, granting them access to their fuel reserves.

Malastare existed inside the system bearing the same name, located in the Dustig sector of the Mid Rim. This world served as a connection point between the Hydian Way hyperspace route—linking it with ZeHeth and Darkknell—and the Biox Detour, which provided a route from Malastare to the Ring of Kafrene mining colony.
Malastare's landscape was dominated by dense forests, while its depths held substantial reserves of fuel. Consequently, the native Dugs cleared significant portions of land, establishing refineries to extract the fuel crucial to their economic system. The sport of Podracing gained considerable popularity on Malastare.

In ancient times, the Zillo Beasts were a major problem for Malastare, preying on the indigenous Dug population. The Dugs discovered that Malastarian fuel was toxic to these creatures and nearly wiped them out. However, a prophecy foretold the eventual return of one, which would bring about the end of Dug civilization. To prepare future generations, a manuscript detailing the Zillo Beasts was passed down.
In the centuries prior to the Imperial Era, members of the Gran species arrived on Malastare with the intention to colonize the world, but they encountered strong resistance from the Dugs. The Gran-Dug war that followed was brutal, with the Gran having a technological advantage, but the Dugs putting up a defense with great resourcefulness and an unrelenting ability. Eventually, the conflict escalated to the point where the Galactic Republic was forced to intervene and establish a ceasefire. Because the Gran colonists had more influence in the Republic than the native Dugs, the Republic essentially handed the world over to the Gran during negotiations via the Gran Protectorate Act. Officially, however, the Gran were given the eastern continent of Malastare, while the Republic relocated the Dugs to the planet's western continent.
By the time of the High Republic Era, Malastare had established the Malastare-Sullust Joint Task Force with Sullust, another world, in order to maintain order in their small section of the Mid Rim, combating pirates and similar threats. Their combined fleet included Hedda Casset, a commanding officer who served in the task force for more than thirty years.
As time passed, Malastare saw an influx of Gran and human populations. Podracing became very popular on the forested planet, and Pixelito became the birthplace of Sebulba, who went on to become one of the most celebrated podracers in history.
During the Trade Federation's Invasion of Naboo, Ainlee Teem, a Gran senator, represented Malastare in the Galactic Senate. After a Vote of No Confidence removed Finis Valorum from office, Ainlee was nominated as a candidate for Supreme Chancellor. However, Sheev Palpatine, the senator from Naboo, was chosen for the position instead.
At one point, a Corporate Alliance fleet, commanded by the brilliant Harch tactician Admiral Trench, blockaded the Malastare Narrows. A Republic task force, led by Wullf Yularen, was sent to engage the corporate fleet. Despite suffering significant losses, reinforcements under the command of Jedi Master Kep-She enabled the blockade to be broken, and Trench was apparently killed. During the Separatist Crisis, Eriadu Mining transported lommite ore through Malastare to the Core Worlds.

During the Clone Wars, the Grand Army of the Republic and the Separatist Droid Army engaged in a battle for Malastare's fuel reserves. Despite the concerns of Nakha Urus, the Doge leading the Dug Council, Supreme Chancellor Palpatine authorized the deployment of an experimental electro-proton bomb. The bomb successfully deactivated the Droid Army, while leaving the Republic's clone troopers unharmed. However, the explosion created a large sinkhole in the ground, swallowing both clones and droids.
While the Dug Council convened to decide whether to sign a treaty that would grant the Republic access to Malastare's fuel reserves, a rescue team led by Jedi Master Mace Windu went into the sinkhole to rescue Republic troopers, finding some survivors. However, they discovered that the bomb had awakened the last surviving Zillo Beast, and they barely escaped with their lives. Doge Urus demanded that the Republic help them eliminate the creature, threatening to cancel the treaty if they refused. Windu refused because it was innocent and the last of its kind. The Supreme Chancellor and Doctor Sionver Boll expressed interest in studying the lightsaber-resistant plates of the Zillo Beast, thinking that they could be used to improve armor for the clone army.

The Republic discovered unprotected gaps between its plates and used RX-200 Falchion-class assault tanks to sedate the creature, leading the Dugs to believe that it was dead. Palpatine ordered it to be taken to Coruscant for study in a controlled environment, despite plans to relocate it somewhere in the Outer Rim. The Malastarian council signed the treaty, giving the Republic access to crucial fuel reserves.
Following the Clone Wars, Malastare came under the control of the Galactic Empire, the Republic's successor. Notably, it housed a significant communications station. Malastare was intended as a target for the Rebel Alliance's 61st Mobile Infantry during Operation Ringbreaker, but the attack was canceled after the siege of Inyusu Tor. Although Blade Squadron successfully targeted it shortly after the Battle of Endor, the Imperial presence remained even after the destruction of the Imperial Future Council on Akiva. Kenner Loring, a Grand General, chose to fortify himself on the planet, opposing Gallius Rax, a Fleet Admiral, who had de facto control over the fractured Empire.

The Dug Council, operating from the Imperial palace, controlled Malastare's internal affairs. The council consisted of five members and was led by the Doge. The council had the authority to ratify treaties. During the Clone Wars, Doge Nakha Urus was the leader.
However, in the Galactic Senate, the Grans exclusively represented Malastare's interests. Aks Moe of the Congress of Malastare represented it during the Trade Federation Invasion of Naboo.
Malastare was initially mentioned in the 1999 movie Star Wars: Episode I The Phantom Menace. It was mentioned once more in a deleted scene from Star Wars: Episode II Attack of the Clones, which was released in 2002. Malastare made its first on-screen appearances in "The Zillo Beast," an episode from the second season of the 2008 animated series Star Wars: The Clone Wars.
The initial hardcover and audiobook versions of The High Republic: The Eye of Darkness included Malastare in the list of planets that had come under Nihil control due to the expansion of the Stormwall. The digital version of the book has been edited to replace Malastare with Elrood as the planet behind the new Stormwall border.