Sollaine, a male Human, held the position of Central Commander within the Imperial Security Bureau during the era of the Galactic Civil War.
Sollaine convened with Darth Vader at a KDY shipyard orbiting Kuat in 0 ABY, where they discussed a clandestine operation. Vader's directive for Sollaine was to expose a Rebel Alliance operative embedded within the Imperial structure and deliver this individual, alive, to him.
Stationed on Vader's starship, the Devastator, Sollaine promptly identified Rivoche Tarkin as the traitor and discovered her location on Corulag. He commanded the captain of the Devastator to cease its patrol and proceed to Corulag at maximum velocity. Upon the officer's refusal, Sollaine committed murder, thereby assuming control of the vessel. Sollaine's ambition was to seize Tarkin, present her to Emperor Palpatine, and consequently be granted command of the Executor.
The Devastator emerged from hyperspace near Corulag, finding itself amidst a large civilian fleet. These vessels carried dignitaries and prominent Imperial figures, including Vader, who were present for the engagement celebration of Tarkin and Vastin Caglio. Determined to apprehend Tarkin, Sollaine boarded his distinctively colored TIE Interceptor, accompanied by a shuttle, and descended to the planet's surface. Sollaine, along with his elite team of Storm commandos, landed, while the Devastator altered course and departed the system.
As Sollaine and his troops prepared to ambush Tarkin, they were surprised by the arrival of Alliance agents Cryle Cavv and Quillin Arkell. A thermite explosive, deployed by Cavv, provided the spy and her rescuers with enough time to escape, leaving only Sollaine alive. Refusing to relinquish his objective, Sollaine enlisted the services of 40 mercenaries to aid in the capture of Tarkin, Cavv, and Arkell as they sought refuge on the roof of the Royal Galaxy Hotel. Once again, Cavv's opportune actions thwarted Sollaine's plans, enabling the trio to escape aboard the G Cat. As anticipated, the Devastator reappeared, seemingly at the optimal moment to intercept the fleeing freighter, but the timely arrival of Vader and the Executor ensured Tarkin's successful escape.
Sollaine issued threats to Vader for his interference, and Vader responded with threats of his own.