Ssith was one of the Serpent-Men, who served the Elder God Set over 12,000 years ago, during the Hyborian Age.
He was a great warrior. He attracted the attention of the time traveler Kang the Conqueror who challenged him to a duel. Kang won and Ssith agreed to serve him. Kang took him to Chronopolis. Ssith served as one of the Anachronauts, warriors who traveled through time when Kang tasked them with missions. Ssith was one of the more bloodthirsty Anachronauts. Despite being from much further in the past than the other Anachronauts (12,000 years ago), he showed no sign of trouble adapting to life in the future.
When the Avengers (Black Knight, Black Widow, Crystal, Hercules, and Sersi) and the Fantastic Four (Human Torch, Invisible Woman, Mr. Fantastic, and the Thing arrived in Chronopolis, Ssith, and the Anachronauts attempted to arrest them. The heroes surrendered, figuring the Anachronauts would lead them to Kang. Unnoticed, Sersi took the form of the Anachronaut Raa. In time, she freed the other heroes and they easily defeated the Anachronauts.
Ssith and the Anachronauts were training and facing each other in mock combat. Then Sir Raston's Ebony Blade began to glow and lost its solidity. Terminatrix determined that this was a result of a temporal anomaly that had the Blade never been created. The erasing of the Blade from history had far-reaching consequences and threatened Chronopolis itself. The Anachronauts time-traveled back to the days of Camelot to undo the anomaly. They found that the Incinerators, a robotic race, had also time-traveled back to Camelot and captured the Star Stone. The Star-Stone provided the material that was used to forge the Blade. With the help of fellow time traveler Justin Alphonse Gamble, the Anachronauts defeated the Incinerators and captured the Star-Stone. Gamble made sure that the Stone would pass to the hands of Merlin who would create the Blade.
Ssith and the Anachronauts defended Chronopolis against the invading forces of Immortus. A "time-twisting explosion" killed most of the team, leaving only temporal shadows of the dead. Only an injured Wildrun seems to have survived.
