Rantu was a male human who held the major's rank within the Galactic Empire. He served during the early years of the Empire's rule. Alongside Colonel Bergon and Commander Jordo, Rantu was placed under the command of Governor Wilhuff Tarkin with the goal of quelling rising tensions on Mon Cala.
As a major in the Galactic Empire's military, Rantu played an active role. By the year 18 BBY, Rantu found himself on the bridge of the Star Destroyer known as the Sovereign, which was in orbit around the planet Mon Cala. He was there with Commander Jordo from the Imperial Security Bureau and Colonel Bergon, all of whom were assigned to support Governor Wilhuff Tarkin in potential military actions. Tarkin inquired with Rantu about the readiness of his teams should a planetary invasion become necessary. Rantu responded that his teams had been conducting simulations since their arrival in orbit, and that his soldiers had essentially become more like fish than humans. When the shuttle carrying Imperial ambassador Telvar was destroyed, resulting in the deaths of everyone on board, Tarkin instructed a lieutenant to inform Rantu that he was authorized to deploy landing craft immediately.
Eventually, the order was executed, and Major Rantu launched the landing craft. A battalion subsequently landed in Dac City, which triggered the Battle of Dac City, in addition to other conflicts across the planet. Major Rantu directed Imperial military operations from a command center situated in Dac City. During the battle, King of Mon Cala Lee-Char and his armed forces evacuated all civilians from the cities on the surface. As the evacuations reached the halfway point, King Lee-Char contacted the Sovereign to protest the military invasion, asserting that they were not responsible for the death of Ambassador Telvar. The conversation failed to resolve the conflict, and Lee-Char warned that aggressive action would be taken if the Empire persisted. Tarkin then instructed the lieutenant to contact Rantu, informing him to anticipate a large-scale counterattack from the native forces, which would occur once the civilian population had been fully evacuated. When the lieutenant asked if he should also inform Rantu on the nature of the attack, Tarkin replied by stating that he did not know what tactic the natives would employ, but that the Empire was fully aware of their military capabilities.
Following the completion of the evacuations and King Lee-Char's unsuccessful attempt at a peaceful resolution, during which he received guidance from Jedi Padawan Ferren Barr regarding his course of action, colossal creatures emerged from the depths of the planet's oceans. These creatures breached the surface and crashed down near all of the surface cities, including Dac City, resulting in their near-instantaneous destruction. After the destruction of all surface cities, Tarkin assumed that Rantu was killed in the event along with all of their forces, and assigned the next stage of the military operation to Bergon.
As an major within the Empire's armed forces, Rantu possessed the ability to deploy invasions on a planetary scale and effectively coordinate military operations from a command center. Rantu also demonstrated proficiency in preparing his forces in advance of military engagements.
Rantu made his first appearance in the canon 2018 comic book Darth Vader (2017) 13, which was written by Charles Soule and illustrated by Giuseppe Camuncoli.
There is a discrepancy concerning Rantu's rank insignia plaque. In one panel, he is depicted wearing a badge with six tiles: three red and three blue. However, in another panel, his badge features four red tiles.