Cosia, a planet located within the Cosian Space region of the Deep Core, resided in the same-named system of the galaxy. This world was the sole inhabited planet in its system, functioning as the homeworld for the Cosian species, a group that included Jedi Master Tera Sinube. The landscape of Cosia featured expansive forests and undulating hills, populated by enormous cosa trees in which the Cosians constructed their cities. Due to the independent nature of Cosia's villages, there was no official capital, but Nu-Cosa was the largest settlement.
Cosia featured several smaller starports and landing areas; the Cosians did not have a formal, large starport on the planet. One such landing area served as a base for the Imperial forces occupying the planet.
Within the Deep Core region of [the galaxy](/article/the_galaxy], Cosia was situated in Cosian Space, within a star system that shared its name. This planet was the only one in its system that supported life, with only one star in the system. Cosia was orbited by two moons, named Tabu and Tebu, which were easily visible in the night sky.
The landscape was characterized by rolling hills, the habitat of the massive cosa tree, which formed the planet's extensive forests. The tree produced massive palm leaves, exceeding one hundred meters in length. Nestled within these forests were numerous Cosian cities, including the largest, Nu-Cosa, all built within the structures of the cosa trees. These cities featured homes connected by intricately carved wooden staircases and elevated walkways made of etched planks and cultivated vines.
At an unspecified time, the Cosians, a reptilian sentient species, emerged within the planet's forests as the only sentient life form on the planet and in the Cosia system. Over time, they established villages across their homeworld, each governed by a council of elders. The hatching of Cosian eggs was marked by a grand celebration, honoring the arrival of new life and wisdom.
Following the rise of the Galactic Empire, Cosia was occupied, and the Empire constructed a starport within the planet's forests.
The sole sentient inhabitants of Cosia were the Cosians, among whom was Jedi Master Tera Sinube. Beyond the sentient population, Cosia was home to insects adorned with vibrant shells and wings, as well as predators that roamed the forest floor.
Numerous Cosian villages dotted the planet, each operating autonomously. Consequently, there was no designated capital city; however, Nu-Cosa was the largest. All villages were constructed within the massive cosa trees, linked by wooden walkways and staircases. Furthermore, each village was governed by a council of elder Cosians.
Due to the independence of each village, Cosia lacked a major starport, but the Galactic Empire constructed one to serve as the center for their occupation.
Cosia was initially mentioned in Star Wars: The Clone Wars Character Encyclopedia, a Star Wars Legends reference book authored by Jason Fry and published in 2010. The world's status as canon was confirmed by the reference book Ultimate Star Wars, released in 2015.