Tar-Vash was a Kree military commander assigned with the stabilization of various border planets of the Kree Empire. He was eventually chosen by the Supreme Intelligence and Ronan the Accuser for mutation to the new Ruul form. The Kree mutated to Ruul could evolve their own bodies to adapt to new enviroments, effectively surviving in situations where a normal Kree would not.

Tar-Vash led an attack on the Toad Men but found his opponents assisted by four Defenders (Doctor Strange, Hulk, Namor and Silver Surfer). He was able to use Power Cosmic drained from the Silver Surfer to enhance the Kree equipment and capture all four super-powered opponents. An amused Tar-Vash started taunting the prisoners, resulting in a berserker rage of the Hulk. The enraged Hulk managed to destroy key equipment of the Kree and forced the entire force under Tar-Vash to retreat. Tar-Vash returned to planet Hala in disgrace.