The Leviathans were a sentient species from the waterworld of Arrakan, characterized by their tentacled forms. The Force-sensitive Leviathan named Kithnarrock, who had lived for a thousand years, was revered as a god by the Battrach on that planet. During the time of the Galactic Civil War, he aided a group of Jedi, along with their allies, in reaching a concealed Rebel Alliance safe haven located off-world.
Arrakan, a waterworld, was the home of the Leviathans. A massive Leviathan, Kithnarrock, was so immense that his full form was difficult to perceive, appearing as a swirling mass of shadows and lashing tentacles. He dwelled in the depths of Arrakan's ocean and, by the era of the Galactic Civil War, had lived for a thousand years. Force-sensitive, Kithnarrock was regularly consulted by the Duor, the dominant sentient species of Arrakan. The Battrach, another sentient species on Arrakan that had been genetically engineered by the Duor, regarded the Leviathan as their god and the creator of their world.
During the period encompassing the Great Jedi Purge and the Galactic Civil War, a party of Jedi and their companions journeyed to Arrakan. Their goal was to obtain the location of a clandestine Rebel Alliance sanctuary from a contact known as "Narrock," who, unbeknownst to them, was actually Kithnarrock. The Duor eventually guided the group to meet the Leviathan. Following a telepathic exchange, Kithnarrock implanted the sanctuary's coordinates into the subconscious of one of the Jedi's allies.
The Leviathans made their debut in the second segment of Phil Sidebotham's roleplaying adventure, "Flight of the Jedi." This adventure was featured in the Spring 2000 twentieth issue of the Valkyrie magazine, designed for use with Star Wars: The Roleplaying Game by West End Games. Given that its publication occurred outside the purview of the Lucas Licensing process, the overall canonicity of the adventure within the Star Wars Legends continuity remained unconfirmed. However, the Leviathans themselves received an indirect mention in the StarWars.com article "Drawing from the Imagination: Mythological Creatures in Star Wars, Part 1," published on October 17, 2013.