Within the Chiss Ascendancy, nestled in the Unknown Regions, resided Ool, a terrestrial planet. Back in 18 BBY, this planet was the home for over two billion Chiss inhabitants and was a well-known destination for those seeking tourism. The terrain of Ool consisted of both beaches and mountains, and it was furthermore a farming world boasting a thriving and varied agricultural industry along with both expansive and smaller manufactory complexes. Mining activities were conducted within its mountainous regions, notably including one of the Ascendancy's trio of pure nyix metal mines. The city known as Pomprey could be found on Ool, and it featured a skybus depot.
The Ardok Ranch was situated in what was known as the "wilds of Ool," and it was under the ownership of Cohbo'rik'ardok, whose core name was "Borika," and her husband, Bomarmo. The Ardok Ranch also housed the Seekers' Shadehouse, a facility associated with the Seekers program that collaborated with sky-walker navigators. In the year 18 BBY, Mitth'ali'astov, a caregiver from the Chiss Expansionary Defense Fleet with the core name "Thalias," paid a visit to the ranch to discuss the issues that Che'ri, her sky-walker, was experiencing with Borika. Their discussion revolved around the sky-walker's training regimen, but Thalias was soon summoned away to the planet of Csilla. After some weeks had passed, she made her way back to Ool, bringing Che'ri with her, so that the Shadehouse could gain knowledge from her problems.
Ool was a terrestrial planet that existed inside the Chiss Ascendancy, which was located in the Unknown Regions of the galaxy. Its atmosphere was breathable for the Chiss species. Besides being an agricultural world, Ool also possessed a variety of mountains and beaches scattered across its surface. The farms contained a selection of domesticated non-sentient animals, such as the packbull. The process of mining occurred on Ool, where deposits of the nyix metal could be unearthed. This planet was the location of one of the Ascendancy's three mines dedicated to pure nyix.
In 18 BBY, on the Ascendancy planet Naporar, Mitth'iv'iklo, also known as "Thivik," who was a Senior Aide from the Mitth family, entrusted Mitth'ali'astov, a caregiver from the Chiss Expansionary Defense Fleet and former sky-walker navigator whose core name was "Thalias," with a data cylinder. This cylinder had been put together by Syndic Mitth'ras'safis, or "Thrass," prior to his death. The data cylinder held information about Ool and the Seekers' Shadehouse, a facility belonging to the Seekers program that worked with sky-walker navigators who possessed unique abilities referred to as Third Sight. This allowed them to guide Chiss ships through the space beyond the Ascendancy's borders, known as the Chaos.
Soon thereafter, Thalias took a break from her responsibilities while the warship she was stationed on, the Chiss heavy cruiser Springhawk, was undergoing repairs at a bluedock above Csilla, the Ascendancy's capital planet, so she could journey to Ool. Ufsa'mak'ro, the Springhawk's first officer with the rank of Mid Captain and the core name "Samakro," informed Thalias that Ool was a flight of one and a half days from Csilla.
Thalias arrived on Ool in search of the Shadehouse, which was not listed in any of the guidebooks she had consulted. Eventually, the caregiver found her way to the Ardok Ranch, using the address provided on Thrass' data cylinder. She was welcomed by Cohbo'rik'ardok, known as "Borika," who co-owned the ranch with her husband, Bomarmo. Because Borika was involved in the Seekers program, she and the caregiver engaged in a conversation about Che'ri, the sky-walker under Thalias' care, and the challenges she was encountering. Thalias started to question the sky-walker's training, but Borika dismissed this and suggested that Thalias could stay at a local inn in the nearby city of Pomprey while awaiting a response.
In time, Borika revealed that a component of the sky-walker training involved erasing the young girls' memories to ensure they would not remember their families and, consequently, would remain in the program. Given that both women had been sky-walkers, this led to a discussion about Borika's suppressed memories. Thrass' data cylinder had revealed that she was the sister of Mitth'raw'nuruodo, a Senior Captain known as "Thrawn," who held the position of commanding officer of the Springhawk. Shortly thereafter, Thalias received a summons back to Csilla, and Borika escorted her to the Ibbian Spaceport so she could board a transport back to the capital.
Several weeks later, Thalias made her way back to Ool, this time with Che'ri, as the girl had finished her campaign alongside Thrawn. Although she was hesitant to remain on Ool, both Thalias and Borika convinced her to stay, emphasizing that sky-walkers were already scarce, and Che'ri's experiences had made her the most exceptional of them all. Borika informed her that what she shared with the Seekers program could assist both her and many sky-walkers in the future.
In 18 BBY, the planet served as a residence for over two billion Cheunh-speaking Chiss. It was also highly regarded as a prominent destination for tourists and travelers, who were drawn to its beaches and opportunities for mountain skiing. As an agricultural world, it featured numerous farms across its surface that supported a thriving and diverse cultivation industry. Ool also accommodated a number of large manufacturing facilities, in addition to thousands of smaller ones. Given that it housed a pure nyix mine and exported the metal, extensive mining operations took place in the mountainous regions of Ool.
The Ardok Ranch, which housed the Seekers' Shadehouse, was located in the wilderness of Ool. The Ibbian Spaceport was a spaceport situated on the planet, approximately one thousand kilometers away from the ranch. The city of Pomprey was also found on Ool, and it contained a skybus depot along with a selection of hotels.
In the current Star Wars canon, Ool made its appearance in the 2021 novel titled Thrawn Ascendancy: Lesser Evil, which was penned by Timothy Zahn as the concluding volume of the Star Wars: The Ascendancy Trilogy. It was simultaneously depicted on a map that publisher Del Rey provided as a preorder bonus for the novel. Within the Star Wars Legends continuity, the planet Ool was first introduced in the 2009 reference book The Essential Atlas, which was co-authored by Daniel Wallace and Jason Fry.
