Purrgil Ultra were a type of the semi-sentient, space-roaming purrgil. They were mostly identical to regular purrgil, albeit with significantly larger heads with slightly different features. In 1 BBY, during the liberation of the planet Lothal from the Galactic Empire's grasp, a group of purrgil and Purrgil Ultra completely wiped out Imperial Grand Admiral Thrawn's blockade. Having established a connection with the purrgil, the Jedi Ezra Bridger then guided three Purrgil Ultra to wrap their tentacles around Thrawn's flagship, the Chimaera, and to jump into hyperspace, removing the Imperial threat from Lothal.
Around 9 ABY, a group of Purrgil Ultra over the planet Seatos helped former Jedi Ahsoka Tano with following the Nightsister Morgan Elsbeth to a neighboring galaxy with the goal of preventing her from recovering Thrawn. The whales transported Tano and the Jedi droid Huyang aboard their T-6 shuttle to the extragalactic planet Peridea.
As a type of purrgil, Purrgil Ultra were semi-sentient, space-dwelling whales that were able to travel through hyperspace, a dimension that allowed traveling at lightspeed. Like other purrgil, they had torpedo-shaped bodies, bulbous heads with two cloudy, blue eyes, four large hind tentacles, multiple fins, and smooth-looking skin of bluish-purple color with gray and yellow portions. Their large mouths were sometimes filled with irregularly spaced, egg-shaped teeth. Others had full mouths of baleen instead of teeth. However, they were significantly larger than regular purrgil, reaching lengths of up to hundreds of meters. They also had more whisker-like organs underneath their mouth and more distinctive protrusions atop their head.
In 1 BBY, during the liberation of the Outer Rim planet Lothal from the Galactic Empire's control, the rebel pilot Mart Mattin, the former Clone Commander Wolffe, and the crime lord Cikatro Vizago sent a signal on Frequency Zero from the modified VCX-100 light freighter Ghost to attract purrgil as part of Jedi Ezra Bridger's backup plan. When a group of purrgil and Purrgil Ultra arrived, they were led by the Ghost and completely destroyed Imperial Grand Admiral Thrawn's blockade of Lothal.
The much larger Purrgil Ultra also damaged the three Star Destroyers hovering in the planet's lower atmosphere above Capital City, including the Chimaera, an Imperial I-class Star Destroyer serving as Thrawn's flagship. Ezra Bridger used the Force to guide three Purrgil Ultra to wrap their tentacles around the Chimaera and to jump into hyperspace, removing the Imperial threat from Lothal.
Around 9 ABY, the Nightsister Morgan Elsbeth and her associates were working on the Eye of Sion, a massive hyperspace transport ring, above the planet Seatos. The planet was on the migratory path of the purrgil as Elsbeth wanted to retrieve Thrawn from a neighboring galaxy. As the Mandalorian warrior Sabine Wren teamed up with the former Jedi Ahsoka Tano and the Jedi droid Huyang on their T-6 shuttle to prevent Thrawn's reappearance—with Wren wishing to find Bridger—they encountered a group of Purrgil Ultra in Seatos' skies. The shuttle had been evading Elsbeth's fighter ships, spearheaded by the Force-users Shin Hati and Marrok. After navigating through the swarm of purrgil and safely descending to a woodland, Wren noted that it was her first time seeing the space whales since the Battle of Lothal.
After Elsbeth's mercenary Baylan Skoll had thrown Tano down a cliff, Wren acquired the Star Map that was being used to determine the hyperspace coordinates for the leap to the adjoining galaxy. Skoll then convinced Wren to hand over the map, claiming it was essential for finding Bridger, and promptly destroyed it, ensuring its secrets remained concealed. Wren was subsequently taken aboard the Eye of Sion, which entered hyperspace despite the New Republic's intervention.
After being rescued by the Ghost, Tano used her psychometry skills to find where Wren went; there seemed to be no way for Tano to follow Elsbeth without the map. However, Tano and Huyang re-entered Seatos' atmosphere in their shuttle, crossing paths with a Purrgil Ultra pod again. Aware that the route to the distant galaxy was deciphered through the purrgil's migratory patterns, Tano exited the shuttle and established a bond with a Purrgil Ultra, which allowed Tano's craft to rest inside its mouth. Soon after, the purrgil jumped into hyperspace, whisking away Tano and Huyang.
On the voyage, Tano recalled the times when Huyang narrated tales about the purrgil to her and fellow initiates in the Jedi Temple on the Core Worlds planet Coruscant. The droid confirmed retaining those stories in his database and began recounting History of the Galaxy, Parts One, Two and Three. As the Eye of Sion emerged from hyperspace nearing Peridea, Skoll noted that the Jedi Archives, the Jedi Order's repository of knowledge on Coruscant, had references to the planet and its ties to the purrgil. Down on Peridea, Elsbeth joined forces with a trio of Nightsisters known as the Great Mothers and Thrawn. The Great Mothers realized Tano had followed Elsbeth, and upon informing Thrawn, the admiral directed Elsbeth to destroy any purrgil approaching Peridea. Exiting hyperspace close to Peridea, Tano and Huyang suddenly found themselves amidst an Imperial minefield. The Purrgil Ultra briefly shielded the T-6 shuttle carrying Tano and Huyang but re-entered hyperspace to avoid the explosives. Pursued by Elsbeth's squadron, Tano and Huyang opted to hide themselves within the planetary ring.
Purrgil Ultra first appeared in "Family Reunion – and Farewell," the last episode of the fourth and final season of the animated television series Star Wars Rebels, which aired on March 5, 2018. They were identified as such in the behind-the-scenes gallery of that episode's guide on StarWars.com, which had been published by March 6, 2018. The creatures were designed by the artist Luke Harrington. Purrgil Ultra made their live-action debut on August 29, 2023 in "Time to Fly," the third episode of the Disney+ series Ahsoka.