Decades ago, a young Xudarian scientist, Tomar-Re, was approached by the Guardians of the Universe to wield the Power Ring of the Green Lantern Corps. Tomar-Re went on to have a long and distinguished career as a Green Lantern. To better perform his duties, Tomar-Re developed the Zathon Ray Communicator which could warn of disasters on other worlds in his sector. Tomar-Re also kept a watchful eye for his neighbouring Green Lantern of Space Sector 2814, Hal Jordan. He warned his fellow ring wielder of any perils, including a violent cosmic storm that once struck Xudar. 
The Xudarians have taken a benevolent interest in the universe they have one of the most peaceful histories in the cosmos. In the 1950s, a Xudarian science expedition came to the planet Earth, but were attacked by the Weaponers of Qward. Apart from Green Lantern representatives the Xudarians have not been seen much in the vicinity of Earth since then.