High Quality Content by WIKIPEDIA articles! Xanthu is a fictional planet in the 30th century DC Comics Universe. Xanthu is a modern world with full membership in the United Planets. Xanthu is the homeworld of Legionnaire Thom Kallor aka "Star Boy" and later aka Justice Society of America member "Starman". He was actually born on an orbiting station above the planet, and his mass-induction abilities are not shared by the natives of his homeworld. Pre-Zero Hour, Xanthu was also home to the super-hero Atmos, who took the role as the primary super-hero on the world given Star Boy being away most of the time. When Atmos went missing, Xanthu attempted to force Star Boy to return full time as their protector.