Tanner Cadaman served as a senator, a human representing his homeworld of Feenix within the Galactic Senate of the Galactic Republic. He openly criticized Supreme Chancellor Sheev Palpatine via media outlets during the Clone Wars and further aligned himself with the Delegation of 2,000, a group expressing concerns regarding the Chancellor's increasing authority.
After the Clone Wars concluded and the Republic underwent a reformation, transforming into the Galactic Empire in 19 BBY, Cadaman was present at Senator Padmé Amidala's funeral on the planet Naboo. The day following the Empire's establishment, Imperial Intelligence arrested Cadaman. He was imprisoned within the Arrth-Eno Prison Complex located on Coruscant, where he perished circa 0 ABY when Palpatine destroyed the prison during what began as a rescue attempt by the Alliance to Restore the Republic, but devolved into an assassination attempt.
A human hailing from Feenix, Tanner Cadaman served as a senator in the Galactic Senate of the Galactic Republic, representing his planet. Throughout the Clone Wars, which pitted the Republic against the Confederacy of Independent Systems, Cadaman emerged as a vocal detractor of Supreme Chancellor Sheev Palpatine's wartime leadership; he often voiced his disapproval to the media. He became a member of the Delegation of 2,000, a group of senators sharing concerns about Palpatine's accumulation of emergency powers during the conflict and the absence of a formal process for their removal.
The delegation submitted a petition urging Palpatine to relinquish these powers during a Senate session that ultimately became the body's last before its transformation into the Imperial Senate as part of the Republic's evolution into the Galactic Empire after the Clone Wars concluded in 19 BBY. Shortly after the Empire's formation, Cadaman was among those who attended the funeral of fellow senator and delegation member Padmé Amidala in the city of Theed on the planet Naboo, participating in the procession behind her coffin alongside other senators.
On the day following the establishment of the Empire, Imperial Intelligence arrested Cadaman, along with other members of the delegation who were branded as traitors by the HoloNet News. Cadaman was subsequently imprisoned, along with other political prisoners, within the Arrth-Eno Prison Complex on the planet Coruscant. Some delegation members who avoided arrest proceeded to establish the rebellious Alliance to Restore the Republic to oppose the Empire. After the Alliance achieved successes against the Empire on Cymoon 1 and elsewhere in 0 ABY, Palpatine—then Galactic Emperor—decreed that all political prisoners held at Arrth-Eno would be executed.
To rescue Cadaman and the other prisoners, rebel Princess Leia Organa and General Davits Draven of Alliance Intelligence orchestrated a mission involving the activation of undercover agent Eneb Ray to extract those held at Arrth-Eno around 0 ABY. Organa provided Mon Mothma, a former senator and leader of the Alliance, with a summary of the mission, expressing her anticipation of seeing Cadaman and others again soon. However, the reunion never occurred, as Ray deviated from the plan and attempted to assassinate Palpatine, ultimately leading to the Emperor detonating a bomb that killed Cadaman and everyone else in the prison. The Empire then attributed their deaths to the rebels. Organa, who had hoped to save Cadaman and the others to compensate for failing to save her homeworld of Alderaan, was emotionally devastated by the mission's failure.
Cadaman was seen wearing a maroon robe.
Tanner Cadaman made an appearance in the prequel trilogy film Star Wars: Episode III Revenge of the Sith, released on May 19, 2005. The funeral scene featuring the character was filmed at Fox Studios, Sydney on September 16, 2003. Within current Star Wars canon, Cadaman was first identified in the 2017 reference book Star Wars: The Visual Encyclopedia.
The name originated within the Star Wars Legends continuity, initially appearing in the article "Republic HoloNet News Special Inaugural Edition 16:5:241," authored by Pablo Hidalgo and Daniel Wallace and published in Star Wars Insider 84 on September 26, 2005. The article did not connect the name to the film character; this association was made in the next issue of Star Wars Insider in Wallace's article "Who's Who in the Delegation of 2000," published on November 28, 2005.