Early Life and Capture
The egg from which Carthoris was born was laid by Dejah Thoris on October 9th, 1866, and he hatched on May 5th, 1876, the very night that his father seemingly died while attempting to restart the atmospheric plant. As such, he grew up never knowing John Carter, though he was not lacking for father figures - he had his grandfather, the jed Mors Kajak and his great-grandfather, the jeddak Tardos Mors, plus Tars Tarkas, the jeddak of Thark (Green Martians are not particularly famous for paternal affection, but Tars Tarkas was different).
Carthoris grew up brave and strong, blessed with his father's agility. In 1884, he set out on a journey and ended up in the Omean Sea, where he was captured by the First Born and brought before the "living goddess" Issus. Carthoris was repeatedly placed in arena, where he was forced to fight the First Born. After defeating his opponents, he would be placed in a prison until the next fight.
Escape from Omean
John Carter and Black Pirate Xodar were placed in the same prison as Carthoris close to a year after he had been captured. Neither John Carter nor Carthoris realized their heritage immediately. Soon after the new prisoners arrived, Carthoris and John Carter were brought to the arena. The first spectacle to take place that day was the slaughter of unarmed women. Angered by this, John Carter leaped into the arena to defend them. Inspired by the earthman, Carthoris rallied the other slaves revolt. Soon he and John Carter had fought their way up to Issus, where they planned on killing her. But she retreated in to a small chute in the ground. Both men followed, the chute leading them into a underground network of tunnels. In the darkness Issus escaped them. Eventually John Cater and Carthoris made their way to the entrance of the tunnel. After sneaking into the prison to retrieve their companion Xodar, all three stole a small vessel and escaped Omean.
Return to Helium
Soon after escaping, their ship began to descend as it had been damaged in the escape. Crashing, their party made it to some small hills before dark. They decided to set up camp. In the morning the discovered that John Carter's companion, Thuvia and camped in the hills as well. She informed John Carter that his friend Tars Tarkas had been taken prisoner by the Warhoons. Ordering Carthoris and the others to stay put, John Carter went off to rescue his friend.
John Carter and Tars Tarkas returned with thoats to ride. The party of five set off for Helium. Not long after, Thuvia spotted the Warhoons bearing down upon them. When she fell off her thoat, Carthoris rode back to Thuvia and threw her upon his thoat. He jumped off the thoat and spurred it in a different direction. The other member of the party rode back to join Carthoris in battle. Just as the Warhoons were upon them, navy ships from Helium flew past and attacked the Warhoons.
After getting rescued, the navy searched for Thuvia but couldn't find her. Carthoris and John Carter found that Dejah Thoris, Mors Kajak, and Tardos Mors had disappeared. All had gone searching for Carthoris but hadn't returned. Zat Arras of Zodanga had taken over command of Helium. The same day Sola, the green martian woman, was found running back to Helium. She reported that Dejah Thoris and Thuvia had been captured the First Born. That very night John Carter, Carthoris and their loyalists made plans to attack Omean. The next day John Carter was discovered missing, but Carthoris continued with the plans.
Carthoris got word that Carter had been captured by Zat Arras, so he sneaked into the prison and freed his father. The warships were ready for attack by now. Carthoris and John Carter mounted a ship and commanded the fleet to take of for Omean.
After declining rule of Helium, John Carter supports his son to fill his great-grandfather's seat until such time that his great-grandfather and grandfather have been found, either alive or dead, and returned home.
When John Carter passed through the Carrion Caves, he sent his faithful hound, Woola, back with a note for Carthoris, giving him information about the frozen north. Carthoris mounts a grand expedition to aid his father, calling on Helium's many ally nations to assist them.
Carthoris Does not appear in the Marvel Comics series.