Fantastic Four #211 (1979)

Given the task of finding Galactus a new Herald in exchange for stopping the villain known as the Sphinx, the Fantastic Four have been teleported to a distant world. Not long after their arrival, they cross paths with some of the locals who warn that they are being chased by beings called the War-Men of Tyros the Terrible, the brutal ruler of this world. When the War-Men attack, Ben smashes one apart revealing that they are nothing more than sophisticated robots. Although the Fantastic Four make short work of the robots, the increasingly weak members of the team pass out due to the ongoing effects of the Skrull aging ray they have been subjected to. As Johnny regroups with the team, he is knocked out by one of the refugees who they saved. He explains to Sue that he is turning them over to another approaching group of War-Men because Tyros punishes those who oppose his rule. The Fantastic Four are then taken prisoner and brought to a nearby city where they are horrified to see its residents living in squalor and poverty. They are soon brought before the planet's opulent ruler, Tyros, who gloats over his new prisoners. He angers Reed when he suggests that he will make Sue one of his slave women, but both he and Ben are too weak to fight back against the greater power of Tyros. Before the alien ruler can slay them, Sue turns invisible and knocks him off balance, deflecting his energy blast. Johnny, having recovered his full strength, flames on and melts their bonds, freeing everyone and a fight breaks out. Outnumbered and overpowered, Tyros begins to cower at his enemies when suddenly he is enveloped in a strange blue glow. Reed points out that Galactus must have stepped in now that they have defeated Tyros. With Tyros defeated, his War-Men are deprived of the power they were provided and now his people are free to reclaim their world. With Tyros as their prisoner, the Fantastic Four are teleported back to the world ship of Galactus. Once more before Galactus, the cosmic being explains that in the past his previous Heralds -- the Silver Surfer, the Air-Walker, and Firelord -- all had a measure of morality to them that ultimately led to them betraying him and leaving his side. He goes on to explain that he has selected the ruthless Tyros due to his lack of morality, hoping that this will suit him better. Galactus then transforms Tyros using the Power Cosmic into his newest Herald: Terrax the Tamer. He then teleports Terrax to the planet below to show off his power to control the very rock and ore of a planet. Terrax uses his power to lift and shatter an entire mountain and then use a chunk to fly out into outer space. Once he reaches beyond the atmosphere, Terrax is given the final gift Galactus has made for him: a powerful, cosmic-powered axe. Terrax then tries to use his new-found power to strike at Galactus, but anticipating this move the Devourer of Worlds gives a show of power, using his vast powers to revert the evolution of Tyros, turning him into various primitive creatures until he finally submits to the commands of his new master. With his new herald in hand, Galactus tells the Fantastic Four that he is now ready to face the Sphinx, and boards his space-faring ship, taking Terrax and the Fantastic Four on board with him, while on the Moon, the Watcher observes Earth, knowing that Galactus will soon come bringing the planet's eventual destruction.