Hannser was a male officer serving within the ranks of the New Republic Defense Fleet.
During the events of the Black Fleet Crisis in the year 16 ABY, he was a member of the task force led by Colonel Ejagga Pakkpekatt, dispatched to find and gather intelligence on the Teljkon Vagabond. In this operation, he held command of the gunship named Marauder.
Later, during the Yuuzhan Vong War, Captain Hannser held the position of commanding officer aboard the Republic-class cruiser known as the Far Thunder. He and his ship, under the command of General Keyan Farlander, participated in the Battle of Obroa-skai, where the Far Thunder sustained significant damage. He vigorously advocated for an attempt to recover the Far Thunder, and his arguments were successful, but the ship was then attacked by a force of Yuuzhan Vong piloting coralskippers.
Although Twin Suns Squadron, under the command of Jedi Jaina Solo, managed to force the coralskippers to withdraw, the Far Thunder was ultimately scuttled by the Lancer-class frigate called the Whip Hand. After being evacuated to the frigate, Hannser was deeply saddened by the loss of his command.
Hannser was a highly capable captain who demonstrated unwavering loyalty to both the New Republic and the crew under his command, irrespective of the specific vessel he was assigned to. While he deeply valued his ships, as exemplified by his attachment to the Far Thunder, he also possessed the good sense to recognize when a course of action was no longer viable and should be abandoned.
Hannser's first appearance occurs in the Black Fleet Crisis novel Before the Storm, penned by Michael P. Kube-McDowell and released in 1996. He reappears in the 2003 New Jedi Order novel The New Jedi Order: Destiny's Way authored by Walter Jon Williams.
Despite the fact that Hannser did not make any further on-screen or in-universe appearances beyond these novels, his character was later included in entries within both the Star Wars Encyclopedia and the Complete Star Wars Encyclopedia.