Hulk saved the train Loki intended for him to destroy, but his actions were misunderstood by Rick Jones. He tried to contact the Fantastic Four to locate the Hulk, but Loki redirected the transmission to his hated half-brother, Thor. Iron Man, Ant-Man and Wasp also intercepted the broadcast, and this led to the formation of the Avengers and Loki’s defeat. Still distrusted by his teammates, Hulk was exploited by a being called the Space Phantom. The cosmic menace impersonated the Hulk and turned the rest of the Avengers against him. The deception was uncovered, but Hulk quit the group regardless, feeling he was hated by the others.
This was not to be the end of Hulk's partnerships with other heroes. He became a founding member of the Defenders along with Dr. Strange, Master of the Mystic Arts, and Namor, the Atlantean Sub-Mariner, to defeat the techno-wizard Yandroth and his ultimate computer, the Omegatron. Thereafter, this loose-knit band of Defenders would unite periodically to oppose threats to humanity. Their numbers grew beginning with the Silver Surfer, Valkyrie and Nighthawk, but members rotated in and out on a frequent basis. Eventually, this informal team dissolved its ranks.
The original Defenders reluctantly re-formed when Yandroth surfaced again to menace the world. Though the heroes defeated his plan, Yandroth used his sorcery to levy a deathbed curse upon their heads, binding them to come together in times of crisis. The curse also had side effect, causing the rationality of the four heroes to be submerged by their more selfish desires. Corrupted by the curse, Strange, Namor, Hulk and Surfer abandoned their fellow Defenders and formed the Order, a group dedicated to ending any perceived threat to world peace by any means necessary. They opposed all who challenged their new world order until the remaining Defenders broke Yandroth's curse and restored the Order's humanity. Afterward, the original Defenders disbanded.