Shyu came from a proud lineage of Fire Sages. His grandfather, Kaja, was Avatar Roku's master during his Avatar training and was later the first person to deny that the Avatar had been killed during the first assault on the Air Nomads. He passed this conviction on to Shyu's father, who became an outspoken critic of the Fire Lord's ambitions, and whose support for the Avatar was branded by the Fire Nation as sedition. After Shyu's father was executed for continuing to profess his loyalty to the Avatar, Shyu was left an orphan. He was taken in and raised by the Fire Sages, though he never felt close to any of them. Despite firsthand knowledge of the penalty faced by defying the Fire Lord's orders, Shyu remained loyal to the Avatar.