As a human male prince, Tal Merrik represented his homeworld of Kalevala within the Galactic Senate throughout the Clone Wars period. He also held a position on the Galactic Senate's Council of Neutral Systems. Secretly, Merrik collaborated with Death Watch, a Mandalorian faction opposed to the New Mandalorians' pacifistic philosophy, aiming to overthrow Duchess Satine Kryze. Merrik's attempt to assassinate Kryze led to encounters with Jedi Master Obi-Wan Kenobi and Jedi Knight Anakin Skywalker. Ultimately, Merrik met his death at the hands of Skywalker on the Coronet.
Serving as a representative for his homeworld of Kalevala, a planet located within the Mandalore system, Tal Merrik, a male human, held a seat in the Galactic Republic's Senate. Unbeknownst to many, Merrik was secretly allied with Death Watch, a Mandalorian terrorist organization, and consequently, with the Confederacy of Independent Systems.

During Obi-Wan Kenobi's visit to Mandalore as an emissary from the Jedi High Council, Merrik was observed alongside Satine Kryze within the Sundari Royal Palace. Kenobi's mission was to investigate allegations of Mandalorian involvement with the Separatists. Merrik displayed noticeable surprise when Kryze challenged Kenobi, whose government had accused her of treason against the Republic. Before Kryze intervened and engaged Kenobi in a verbal exchange, Merrik attempted to address both Kenobi and Prime Minister Almec. Kenobi then revealed that the Jedi Council had assigned his mission, silencing Kryze, who had presumed he was acting on behalf of the Republic. Afterward, Kryze and Kenobi embarked on a walk through Sundari, the domed capital city of Mandalore.

Later, Merrik found himself aboard the Coronet, a luxurious starship utilized for transporting members of the Council of Neutral Systems to Coruscant, the galactic capital world. Jedi Knight Anakin Skywalker, Kenobi, in addition to several clone troopers, were also present to provide protection from a potential Death Watch attack. Merrik questioned the Duchess regarding the Council's stance against the Clone Wars. Kenobi entered the room and continued his debate with Kryze concerning the value of Jedi involvement in the war, before Orn Free Taa interrupted them. Merrik and Taa concurred that both Kryze and Kenobi demonstrated the existence of two perspectives on every issue.
Subsequently, Kenobi and Kryze resumed their debate, only to be interrupted once more by Merrik, who suggested that everyone could benefit from rest and refreshments. Kryze then promptly exited the room, while the others, including Kin Robb and Onaconda Farr, observed in silence.

Farr, Kryze, Robb, Merrik, and Taa shared a dinner consisting of deep-fried nuna leg on the Coronet. Kenobi entered the room and informed the senators that the clones were investigating a disturbance on the lower decks. Merrik watched as Kenobi received a communication on his comlink revealing that a container had been opened and emptied. The container held assassin probes, one of which was deployed in the lower levels, while the other had ascended via the elevator. The second assassin probe quickly arrived at the dining area and prepared to attack the senators before Kenobi destroyed it.
However, the assassin probes released smaller SD-K4a mini-assassin droids that swarmed the room. Kenobi used his lightsaber to destroy many, while Kryze used her blaster pistol to deactivate them. After a brief return to dinner, Kenobi arrived with one of the probe killers in a container. Kenobi used the probe to identify the traitor by observing which senator it would not attack. Upon realizing that Merrik was the treasonous individual, Merrik swiftly retaliated and took Kryze hostage.

Holding a blaster to Kryze's head, Merrik escorted the Duchess from the dining area to the ship's helm, where he promptly eliminated all the pilots and contacted Pre Vizsla. Death Watch informed him that reinforcements were en route, just as three Droch-class boarding ships carrying B2-series super battle droids arrived on the Coronet. Merrik, who had secretly rigged the starship's engines to explode with the press of a button, threatened Kenobi as a battle unfolded across the ship between the droids, clone troopers, and Mandalorian Protectors.

As Merrik attempted to escape, Kryze declared her love for Kenobi, who reciprocated, much to Merrik's annoyance. She then insulted Merrik, calling him a slug for his betrayal, stepped on his foot, and seized his blaster. As they both aimed their weapons at him, Merrik expressed amusement, believing that neither of them would kill him, as Kryze would be seen as a hypocrite to her pacifist beliefs and Kenobi would be seen as a hero to everyone but the Duchess, who would be disgusted. Merrik then tauntingly asked who would brand themselves a killer in striking him first. However, Anakin Skywalker, unnoticed, approached the unsuspecting senator from behind and killed him by impaling him through the chest with a lightsaber.
Tal Merrik made his debut in "The Mandalore Plot," the twelfth episode of Star Wars: The Clone Wars' second season. His identity was confirmed in the credits. Greg Proops provided his voice, having previously voiced Fode in The Phantom Menace. Some early production concept art of Merrik seems to depict the character as female; using an existing generic female Mandalorian citizen asset as a basis.