Tyros was once the dictator of the city Lanlak on the planet Birj, where his superhuman ability to command rocks and earth enabled him to overcome all resistance. His rule of Lanlak came to an end when he was sought by the world-devouring Galactus to serve as his newest Herald. Galactus sent his sometimes-adversaries of the Fantastic Four to apprehend Tyros and bring him to receive the Power Cosmic. Tyros resisted them, but to no avail. Galactus made Tyros his new Herald Terrax, and the power cosmic magnified his abilities, making him far more powerful than he had been before.
Terrax proved to be the most troublesome Herald to ever serve Galactus. Although he led to devour many worlds, Terrax wished to use his powers for personal gain, and only fear of his master kept him in line. He once fled Galactus' service to set up his own empire, but Galactus empowered the Earth woman, Alison Blaire (also known as Dazzler) to retrieve him. Finally, Terrax kept Galactus from feeding long enough that his energies dwindled, and he finally led him to Earth in the hopes that the Fantastic Four would help him slay his master. Galactus withdrew the power Cosmic from Terrax to replenish his own spent energies, and left Terrax stranded on Earth.
The dictator Victor von Doom was able to restore some of Terrax's power to him to use against the Fantastic Four, but in battle with the Silver Surfer, Terrax was consumed by the Power Cosmic and killed. His body later regenerated itself on Earth, but the Surfer exiled Terrax to an uninhabited world.
Terrax was released from his exile to aid fellow Heralds Firelord, Nova, the android Air walker and the Silver Surfer against Morg. Terrax slew Morg with his own axe, which he kept as spoils of the battle, Morg was later resurrected.
As the Annihilation Wave began its search for Galactus' Heralds so that Annihilus could study the Power Cosmic, Terrax was one of the first to be captured by the Seekers of Annihilus and taken into custody. Terrax was eventually freed from his captors' control and exacted his revenge upon them. Afterwards, he, Paibok, the Power Skrull and the Infant Terrible journeyed to a world inhabited by Centaurians and saved them from the deadly Space Parasite. After cleaving the monster in two, Terrax left the others planet side claiming it was time for him to show the universe why Terrax, the Tamer should be feared once more.
Recently, the Red Hulk recruited Terrax, along with Tiger Shark and Baron Mordo, to become part of the Offenders to take part in a death duel against the Hulk and the Defenders. Terrax was matched up against the Silver Surfer in the Microverse, but neither could gain the upper hand. Because the contest was too evenly matched, Psycho-Man was introduced into the game by the one who started it all in the first place - the Grandmaster. Psycho-Man used his control box to manipulate the emotions of Terrax and the Surfer into submission. After the Red Hulk had triumphed in his contest with the Hulk, the Grandmaster inserted the red behemoth back into the game, and he destroyed Psycho-Man's armor and the entity inside. With Terrax free of Psycho-Man's control, he was ready to rid the universe of the Silver Surfer with his teammate's help. Red Hulk had other plans, however, and beheaded Terrax with his own axe. Toward the end of the game, Grandmaster revealed he had revived Terrax and placed him back in the time stream where he was found, with no memory of the event.