He was a prince of the Hyksos, a people who invaded and ruled Egypt from 1670 to 1570 B.C. Khyan was born c.1600 B.C. and was adopted by the king of the Hyksos. He was raised alongside the king's son, Apohis, as his brother. Only the king and Apophis knew that Khyan was adopted. In 1578 B.C., during a hunt with his brother, Khyan killed a lion, but died in a sandstorm on his way back.
Khyan revived as an Immortal, and didn't know what had happened to him. At this point he was still very young, in his twenties. Khyan was also mentally unstable. He suffered from violent nightmares, and killed servants because he thought they were demons. He soon noticed that he did not age and apparently could not die. Khyan believed that it was the god, Seth, who had blessed him.
Around 1573 B.C., he finally met another Immortal when he was sent to Thebes by his brother as the Hyksos envoy. He encountered an Immortal in Pharoah Kamose's court, who called himself Methos. Methos, for his part, was unhappy not only to meet another immortal during such a precarious time, but one who clearly seemed unstable as well. He kept Khyan off balance by trying to build a camaraderie: "The two of us are so much more than those petty little people. Have we not been both touched by divine forces? That makes us brothers, Prince Khyan, not enemies....And there shall be peace between us." He then used Khyan to infiltrate the Hyksos court.
In 1570 B.C. the Egyptian army faced the Hyksos invaders. Khyan and his brother Apophis were captured and imprisoned. To his surprise and rage he encountered Methos again who was helping Pharaoh Kamose. Apophis was killed ritually, the priests determined his soul was to be captured and sealed into a sword. When Apophis was dead, the frantic Khyan called Methos demon, and laid the death of his brother at his feet. He broke away from his captors and drove a sword through Methos' chest, killing him. Unfortunately, though Khyan was prevented from taking Methos' head, Methos did revive in front of numerous witnesses. Khyan was then shot to death by bowmen, and Methos was extracted from the chaotic scene and sent on his way by one of the Pharaoh's soldiers, a man with whom he had fought, and who regarded him with respect no matter what he might be.
Khyan managed to survive for thousands of years. He lived a relatively normal life, but in the year 1999, his visions returned, even worse than before. He had learned that the ancient Hyksos blade, the sword that he believed held his brother's soul, was part of an display somewhere in New York. Khyan tried to locate it, and began to kill mortals in ritualistic sacrifices. After he had killed six people, he still hadn't a clue where to find the sword.
Finally, he came across a message that was written in the Hyksos language, a flyer posted in Riverside Park where his victims had been found. It was a call to a meeting. When he came to the given place, he faced Methos and Duncan MacLeod. He then had his final duel with Methos. In the end he fell off the roof and was killed and was then beheaded by Methos.