The Cantrosians were a race of intelligent felinoids from the world of Cantros 7, possessing sapience. A consequence of scratches inflicted by their claws was the contraction of Cantrosian-scratch fever. During the period of the Galactic Civil War, the Cantrosians demonstrated strong support for the Rebel Alliance, an allegiance that triggered an internecine conflict following the actions of a rogue operative who attempted to turn factions against one another by suggesting Imperial sympathies within certain Cantrosian factions.
Cantrosians represented a species of humanoids with feline characteristics. Distinctive features included triangular ears, sharp teeth, small noses and whiskers, all covered by a coat of fur. The color of this fur exhibited significant variation, ranging from gold to blue and white. Similarly, the eyes displayed a spectrum of hues among individuals, with green and orange being notable examples. The species comprised two distinct genders: male and female. Females were characterized by the presence of hair on their heads, sometimes featuring streaks. While some male Cantrosians also possessed hair, others did not. Their claws, present on all five digits of their paws, were capable of transmitting Cantrosian-scratch fever. Cantrosians also utilized clothing, including items like jumpsuits as well as boots.

The Cantrosians displayed a notable level of technological advancement, as evidenced by their capacity to create fire, pilot starships such as the T-65 X-wing starfighter, and operate blasters. They also possessed a sophisticated understanding of political concepts, with many Cantrosians expressing unwavering allegiance to the Rebel Alliance. Their homeworld, Cantros 7, featured a designated capital. Certain Cantrosians did not reject the use of torture when deemed necessary.
In the year 4 ABY, a Cantrosian male named Durne was employed by Nagai Commander Knife—who himself was working to destabilize the Saijo sector under the direction of the Sith Lady Lumiya—to incite conflict among his people by falsely portraying some Cantrosians as sympathizers of the Galactic Empire, thereby dividing the Rebels into opposing groups. Durne successfully executed this plan, which resulted in factions fleeing Cantros 7 and establishing bases in different locations. Durne then integrated himself into one of these factions, feigning friendship with Minka and Sami, two members of the group. Minka and several others were subsequently assigned to a spy mission targeting a base within the Cantros system, where another faction had sought refuge.
Following the gathering of intelligence, the spies traveled to nearby Saijo to convey their findings to their allies; however, they were pursued by three Y-wing starfighters, piloted by Cantrosians from the opposing faction, resulting in the deaths of several pilots from Minka's team. Minka survived, but her fighter sustained significant damage and crashed on Saijo. Rebellion figureheads Luke, Leia, and Han were present on the planet and utilized the cannons of the Millennium Falcon to neutralize the Y-wings. After Minka's recovery, the Rebellion heroes transported her to Saijo, where she introduced them to other Cantrosians belonging to her faction. Minka and Sami resolved to retaliate, but Durne, seeking to maintain his deception, concocted a false narrative and secretly traveled to the enemy base.

As the group journeyed in the Millennium Falcon toward the opposing faction's planet, they came under fire from additional rival Y-wings, forcing the Falcon to make an emergency landing in a ravine on an asteroid. Sami, Solo, and Skywalker were captured by the Cantrosians residing there, while Minka and Organa managed to escape. At the base, Sami and his companions faced the threat of torture, but the faction's leader, Niru, objected, asserting that torture was a practice of the Empire, thereby revealing her faction's true allegiance. Durne made an unexpected appearance and exacerbated the situation by encouraging Niru to torture their captives. An enraged Sami, along with Solo, exposed Durne's treachery and affirmed to Niru that they, too, were Rebels.
Minka and Organa arrived and disarmed Durne, triggering a firefight when the faction mistakenly identified the two as potential Imperials. Niru refused to fire and attempted to de-escalate the situation, but Durne, assuming that Niru's death from an 'unidentified source' would restore his control, attempted to attack her by surprise. Skywalker activated his lightsaber and deflected Durne's fire, incapacitating him. Upon witnessing this, the assembled Cantrosians recognized the truth of the deception. As Solo clarified the misunderstanding, Durne attempted to flee, but Niru successfully apprehended him. With tensions eased, the Cantrosians decided to return to Cantros 7 and co-exist peacefully. They took Durne with them, intending to uncover the truth through proper interrogation.
In 19 BBY, at least two Cantrosians were present on the Core Worlds planet of Coruscant; after reprimanding a Herglic for colliding with him, Sullustan reporter Den Dhur noticed the pair and mused that he would have been more courteous toward them, given the risk of contracting Cantrosian-scratch fever if he provoked them. As of 1 BBY, an elderly female Cantrosian resided on Malastare, where she sold pashi noodles from a street stall; Juno Eclipse, an Imperial pilot who would later join the Rebellion, was among her customers.
The Cantrosian species made its initial appearance in the 1984 issue Star Wars (1977) 93 from Marvel Comics, with artwork by Sal Buscema and coloring by Petra Scotese. The species received its name in Michael Reaves' 2008 novel, Coruscant Nights II: Street of Shadows.