Desmund Pitt was a major in the United States Air Force when he met test pilot, Ben Grimm. In short order, he and Grim, who would later become the Thing, a member of the super team Fantastic Four, became close friends. During a brief return to civilian life, Pitt married and had a son. Eventually, Pitt rejoined the Air Force and was assigned to the Kennedy Space Center in Houston, Texas. There he was placed on the staff of a research project designed to develop the solar shuttle (a variant on the space shuttle.) As Pitt became involved with the early stages of the project, his wife was diagnosed as suffering form a terminal illness. The prognosis gave her only a few months to live. While under the great emotional stress which accompanied knowledge of his wife's condition, Pitt also discovered that the solar shuttle project had been infiltrated by agents of Victor von Doom, absolute monarch of the Balkan state Latveria.
 

In an effort to learn the extent of the infiltration and its purpose, Pitt decided to present himself as a willing collaborator. Fearful that the spy network may well have extended into other areas of NASA, Pitt told no one of his plans, not even his superiors. Attempting to gather as much information as possible, he became the confidante of the ring's leaders. They were so impressed by Pitt that they brought the major to the attention of Dr. Doom himself. To all appearances, Pitt was a loyal spy. He soon learned that Doom's men meant to utilize the awesome powers of the solar shuttle to energize solar panels in Latveria.

Before Pitt could expose the plan to United States government officials, his wife died. Grief-stricken, Pitt became careless with his ruse and Doom discovered that he was a double agent. Doom's operatives in high NASA positions denounced Pitt as a traitor. Before he could be arrested, Pitt disappeared. U.S. officials deduced that he had been killed.

In reality, Pitt had been kidnapped and brought to Latveria. Doom wised to make an example of Pitt to other individuals who might dare to might dare to consider betraying him. Pitt was forced to undergo chemical and cybernetic transmutation. Under Doom's direct supervision, Pitt's body was reformed to resemble a legendary demon that supposed haunted the mountains of Latveria. Code-named Darkoth the Death Demon, Pitt was given extraordinary strength, agility, and limited psionic powers. The final process in the creation of Darkoth was exposure to Doom's vibration device, erasing his personality and memories. Doom also implanted a hypnotic suggestion that Pitt was in reality a demon, who had been rescued from the Netherworld by Doom to be his personal warrior. As such, PItt became the most loyal servant of the man who made him a monster.

Aware of Pitt's past friendship with Ben Grimm, Doom utilized Pitt in the capture or the Thing while he was in a neighboring country. After the rest of the Fantastic Four were subsequently captured, Doom's revenge on Pitt was complete: he had helped in the defeat of his best friend and his partners. In hopes of forever breaking Pitt's spirit, Doom revealed the truth about his origin. However, the realization of the truth released Pitt from his brainwashing.

Pitt freed the Fantastic Four and helped in defeating Doom and his latest world-conquering plan. Nevertheless, Pitt concealed the truth from Grimm for unknown reasons. Pitt followed Doom, who tried to escape in a spacecraft, and continued to battle against him. The craft collided with a satellite, sending the two hurling back toward Earth.

Pitt survived the re-entry, crashing into the Texas desert. He was discovered and recovered by the Fantastic Four villain, Diablo, master alchemist. Diablo used a variant of his own life-prolonging potions to save Pitt's life, but also used his powers to grant Pitt new powers and to submit Pitt to his will. Diablo learned from Pitt about the solar shuttle and its imminent launch and intended to use the shuttle's solar generators to destroy his long-time enemy, Dr. Doom. Pitt agreed for reasons of his own revenge, but rebelled when he learned the pilot of the shuttle would be the Thing.

Warned by Pitt, the Thing was able to destroy the solar generators and prevent Diablo's plan. Enraged, Diablo sought to kill the Thing by subjecting him to lethal radiation. Witnessing this, Pitt freed himself from Diablo's domination and revealed to his old friend his true identity. He save the Thing's life by hurling both Diablo and himself into the exploding solar generators. The Thing managed to escape the holocaust, but Pitt was assumed killed.