The war-torn planet Xandar is a world of triumph and tragedy, traits embodied by its Champions. A scientifically advanced humanoid alien race from the Tranta system of the Andromeda Galaxy, the Xandarians maintained a super-powered militia known as the Nova Corps, as well as energy-absorbing Syfon warriors. Despite these defenses, Xandar was invaded by the Luphomoids, who sought to seize Xandar after their own planet was consumed by Galactus. The war wiped out the Luphomoids and blew Xandar to pieces, though the planet's four largest fragments survived as a network of interlinked settlements through the aid of Uatu the Watcher.
Thinking Xandar totally destroyed, Nova Corps leader Rhomann Dey pursued Luphomoid leader Warlord Zorr to Earth, where the dying Dey transferred his Nova powers and uniform to human teen Richard Rider, who helped destroy Zorr. Rider used his new powers to become the super hero Nova, battling foes such as the amnesiac Syfon warrior Powerhouse, the gem-bodied Diamondhead, the immortal Sphinx, and the cyborg Doctor Sun; he also befriended fellow heroes such as the high-tech vigilante Crimebuster and Crimebuster's long-lost father, the electrical-powered 1950s super hero known as the Comet. The Sphinx ultimately manipulated these six other heroes and villains into helping him fly the late Dey's Nova Prime starship back to Xandar, which was now at war with the invading Skrulls. The Sphinx vastly enhanced his powers and knowledge by tapping into Xandar's Living Computers (housing the collective memories of millennia of Xandarians) and became an even greater menace, but was soon defeated by the Fantastic Four with the aid of Galactus; however, the Sphinx's ex-shipmates (minus Doctor Sun) banded together to defend Xandar as the planet's new Champions. Soon joined by Nova Corps leader Tanak Valt and the Protector (caretaker and avatar of the Living Computers), the Champions became Xandar's foremost warriors.
The Skrull-Xandar war was a long, bloody conflict that eventually exposed a traitor within the Champions: Diamondhead, still an unrepentant villain at heart, betrayed the Xandarians to the Skrulls, resulting in the death of Crimebuster and the penetration of Xandar's defenses by a Skrull army. Despite this, Xandar's forces prevailed with the aid of the Spaceknight Rom and dealt the Skrulls a decisive defeat. With peace restored, a homesick Richard Rider returned to Earth, forfeiting his Nova powers since they were reserved for the defense of Xandar. In his absence, Xandar was invaded yet again, this time by the forces of the space pirate Nebula (daughter of Zorr), who reportedly wiped out the entire population, including the remaining Champions. As she died, Xandar's Queen Adora restored Rider's Nova powers from afar.
Years later, contingency plans set in motion by Protector and Adora before their deaths reactivated Xandar's computerized Worldmind (now programmed with a facsimile of the Protector's consciousness), which began resurrecting Accra and other Xandarians in cloned bodies; Xandar rose from the ashes yet again. The Nova Corps has been rebuilt as the Xandarian Star Corps and Rider sometimes works with them in addition to his Earthly super heroics, but it remains to be seen whether any of the lost Champions will be found or resurrected. Diamondhead returned to crime on Earth but was shattered in battle with Nova. For now, Richard Rider is the sole known survivor of the Champions of Xandar.
Not long ago, the Annnihilation Wave army led by Negative Zone tyrant Annihilus utterly destroyed Xandar, killing the entire Nova Corps except for Nova (Richard Rider). As the last Nova and reluctant host of the Worldmind's intelligence, Rider was all that remained of both the Champions and Xandar itself, striving to uphold the noble legacy of his fallen comrades. More recently the Worldmind had sought revived the Nova Corps and against the wishes of Richard Rider the young recruits were rushed into battle against the avian Shi'ar empire. The new Corps met a quick and brutal defeat at the hands of the Imperial Guard.
