Taszar graduated early from military training in 2554, at the age of 18 human years. Although this was mainly because Arbiter Thel 'Vadam wanted the Sangheili force to have bigger numbers in preparation for war against The Fallen, Taszar would become a very distinctive soldier. In 2559, he helped hunt down members of The Fallen after hundreds of Sangheili newborns were kidnapped by their leader, Isto 'Vadum. He was forced to take the Spartans into custody after they were suspected of helping them. Taszar was assumed to have helped free the newborns in Isto's corvette, and returned to Sanghelios.
In 2568, Urei 'Cazal had located a powerful Forerunner artifact known as the Light of the Abyss that would have turned the tide of the Sangheili conflict against them. However, the artifact was found first by Taszar, who also at the same time crippled the Fallen's resources with the secrets he discovered. In addition, he had discovered their key hideout, which would be destroyed by SPARTAN-IIIPhoenix Team several months later. This feat earned him the rank of Field Master later that year.