A descendant of Sir Percy of Scandia, the original Black Knight from Medieval times, Nathan Garrett inherited Garrett Castle, the final resting place of Sir Percy. There, the spirit of Sir Percy appeared to him, charging him with becoming a modern-day crusader for good as a new Black Knight. However, Nathan proved unworthy and could not draw Sir Percy’s enchanted Ebony Blade.

At some point, Nathan Garrett had become a Communist spy for the People’s Republic of China. He left his teaching position at Oxford University and became a U.S. citizen working for a research lab. He was also head of an espionage ring, selling American scientific secrets to China, until he was captured by Giant-Man (Henry Pym). He managed to flee to an undisclosed location in the Balkans where he decided to become the Black Knight, albeit one for criminal gain. With his new costume and weapons, he returned to America, but his first attempt at a robbery was thwarted by Giant-man, and he escaped again.

The Black Knight was contacted by Baron Heinrich Zemo to help form the original Masters of Evil as a counterpart for the Avengers’ Giant-Man. However, Zemo’s plan, to defeat the Avengers and hold New York in thrall, failed, because the Avengers switched up opponents and the Black Knight was beaten by Thor. He escaped prison once to battle Iron Man, but he was defeated and remanded to custody again. Broken out of prison by the Enchantress and the Executioner, he joined another version of the Masters of Evil, but was again defeated by the Avengers.

The Black Knight again tried to focus his efforts on defeating Iron Man by kidnapping Tony Stark’s friend Happy Hogan and holding him in a castle that was reconstructed in Washington D.C. The Knight actually succeeded in defeating Iron Man by disrupting the circuitry of his armor, and he flew with him into the sky, hoping to drop him from a great height. Instead, Iron Man managed to unhorse the Knight and they both fell. Iron Man’s armor recovered enough to fly him to safety, but the Black Knight was believed to have perished in the fall.

On his deathbed, the Black Knight reached out to his only living relative, Dane Whitman, and revealed the truth about his secret identity. Full of regret, he charged his nephew with using his weapons and technology for good instead of evil. Nathan Garrett died, but Dane Whitman fulfilled his promise by becoming the heroic Black Knight.

Years later, Nathan Garrett was resurrected by Immortus as a part of his Legion of the Unliving. Immortus pitted the Legion against the Avengers as he hoped to enslave the Scarlet Witch and thus control time itself. The Black Knight was a merciless version of himself, but he was nonetheless defeated along with the others on his team. He was seen again as a member of another Legion of the Unliving, resurrected by the Grim Reaper into the body of a plane crash victim. The Legion, little more than violent, mindless zombies, battled the Avengers on behalf of the Reaper, who was seeking revenge on the Avengers for supposedly killing him. When confronted with the truth of his own suicide, the Reaper lost control over the souls of the Legion, which returned to the afterlife, and succumbed to the demon, Lliogoroth, who was feeding him power.