Yaun, a Human individual, held the position of senator, representing the interests of Bureaucratosis within the Senate of the Galactic Republic. Their senatorial duties were carried out on Coruscant, a prominent planet, during the tumultuous period known as the Clone Wars. During one particular session, Yaun was giving a speech to the Senate, but their address was cut short by Han Solo who was disguised as an orphan. This interruption led to a heated confrontation erupting between Yaun's supporters and the Wookiee delegation present within the Senate Chamber.
Following the reorganization of the Republic, which led to its transformation into the Galactic Empire, Yaun remained in their senatorial role, now representing Bureaucratosis within the Imperial Senate. Around the time of 0 ABY, Emperor Palpatine took the action of removing Yaun, along with all other senators, from the Senate Building. However, upon discovering that Yaun had remained behind, Palpatine forcibly ejected the senator from the chamber using a blast of Force lightning.
As the Clone Wars raged, a period spanning from 22 BBY to 19 BBY, Yaun took on the responsibilities of a member within the Galactic Republic's governing body, the Senate, where they were the representative for Bureaucratosis. At some point during Yaun's service, a group of Jedi younglings embarked on an excursion led by the protocol droid C-3PO and his astromech companion, R2-D2. This trip included observing a session of the Senate held within the Senate Building on the planet of Coruscant. The Supreme Chancellor, Palpatine, initiated the meeting and granted Yaun the opportunity to address the assembled senators. Floating within their designated Senate pod, Yaun presented themselves before their colleagues and commenced their speech.
One of the younglings, who went by the name "Ian" but was actually a young Corellian orphan known as Han Solo, attempted to evade detection by Coruscant's security forces by detaching the Jedi pod from its docking station. This action resulted in the pod crashing directly into Yaun's pod, which was also occupied by their aides, and subsequently colliding with the pod housing several Wookiee delegates. In response, the Wookiees rammed Yaun's pod with their own, prompting Yaun to retaliate in kind. C-3PO attempted to intervene but was ejected from his pod and landed on the Supreme Chancellor's control board, causing all the pods to detach from their docks and creating further chaos. Soon after, Yaun attended a ceremony held on the steps of Coruscant's Jedi Temple to honor the younglings and their heroic actions. The senator applauded the young Jedi and waved to the crowd while enjoying the fireworks display.
After the Republic went through a transformation to become the Galactic Empire, Yaun continued their service as the representative of Bureaucratosis in the Imperial Senate. Around the time of 0 ABY, the Galactic Emperor Palpatine, accompanied by his apprentice, Darth Vader, visited the Senate Chamber to examine old Jedi holocrons in search of rebellious planets that needed to be suppressed. Vader questioned the absence of senators, to which Palpatine responded that he had "kicked 'em all out," having dissolved the Senate. However, this statement was contradicted by Yaun, who was absentmindedly whistling from their Senate pod. Annoyed, Palpatine told Yaun to "vamoose." The senator blah-ed a startled response, leading Palpatine to unleash Force lightning upon them, forcibly removing them from the chamber as Yaun cried out.
Yaun was a Human individual characterized by their light complexion. They had a wrinkled face, a bald head, and white facial hair. The senator primarily communicated through "blah" sounds, although they were capable of other speech, as demonstrated by their affirmative response to Palpatine. C-3PO described Yaun's verbose communication style as "glorious."
On one occasion, Yaun retaliated against a group of Wookiee delegates because they believed that the Wookiees had intentionally collided with their Senate pod. They also defied Palpatine's order to evacuate the Senate Chamber and, while lingering there, engaged in reading a book.
Yaun was typically seen wearing white robes, a blue undershirt, and a white cape, an attire also worn by their aides. In their capacity as a senator, Yaun occupied a repulsorpod located within the Senate Chamber. By the Imperial era, Yaun was in possession of a blue book.
Yaun made their debut in LEGO Star Wars: The Padawan Menace, an animated television special that was first broadcast on July 22, 2011. The closing credits did not identify the voice actor for Yaun, and the correct spelling of Yaun's name was not officially confirmed until it appeared in the subtitles of the special's Blu-ray and DVD release on September 16 of the same year. The character reappeared in "Raid on Coruscant," an episode of LEGO Star Wars: The Yoda Chronicles that was released on September 7, 2014, with Michael Daingerfield providing the voice. Notably, Daingerfield's name was not included in the credits of the original special.