Yandroth was an alien humanoid scientist who fought Doctor Strange on several occasions. Strange defeated Yandroth, sending him to seemingly fall forever through an alternate dimension. There, he learned that he could gain great power by destroying a world. He constructed an 'Omegatron', which was defeated in the Defender's first adventure.

Omegatron menaced the Defenders a few more times. Later, Yandroth possessed a young girl in order to telepathically attack the heroes. He was seemingly killed in their last encounter. Although Yandroth was dead, his spirit was still capable of taking possession of a living human's mind. Taking the form of a vagrant, he was discovered by Patsy Walker. Seemingly an innocent, she rescued him, allowing him time to regain his strength and capture her.

He crafted a plan to end the world. He utilized the captured form of Gaea, the spirit of the Earth, to summon monsters from all over, involving many superhero teams. Most of the New York-based heroes were tied up confronting destructive, mindless monstrosities. Alpha Flight was attacked by Warlord Kaa and his Shadow Warriors. A group of Living Erasers appeared in the Tokyo Headquarters of the Big Hero Six. Lizard Men from Tok attacked the island nation of Genosha. Gorgilla subdued the Avengers by dropping a building on them.

Patsy, who had escaped and learned this, told the Defenders, who were then comprised of Namor, the Hulk, Doctor Strange and Silver Surfer.

The superhero battles Yandroth had caused had given him enough power to summon the Ravagers of Creation. Four elemental creatures confronted the Defenders, who were unable to stop them individually. They attacked the Stone creature, disabling the spell needed to destroy the world. This freed Gaea and killed Yandroth.

As he witnessed the Hulk and Namor fighting, he realized the Defenders hated each other. With his last breath, He used his powers to curse them, so they would be forced to work together in times of a severe crisis. This involved uncontrollable teleportation, affecting all four of the heroes.

Yandroth was later revived when the four Defenders became The Order for a short time and their curse rendered him all-powerful.