Thanagar
Home to the Thanagarians, a race of avian warriors.
Thanagar is home to the Thanagarian Empire, a civilization spanning numerous solar systems.
Thanagar might not have merited any special attention from the elder races except for three reasons: Thanagar was located relatively close to warmongering Asgard; it was a culture with a strong military tradition and warlike demeanour; and they possessed a rare, unique alloy called 'Nth Metal'. Among its many remarkable properties, it was primarily useful as a tool for negating magic.
With the acceleration of Asgardian aggression causing strife through the sector, the Guardians of the Universe-- those long-lived strategists of Oa-- sought a tool to curb Asgardian expansionism the restoration of the Demiurge ca 2500 BCE. They covertly uplifted Thanagar into a Type II civilization and ensured that the Thanagarians and Asgardians would find common ground to contest.
The Thanagar 'Hawkmen' were an army of excellent fighters and their magic-negating weaponry gave them even footing against the mighty Asgardian soldiery. By 2000 BCE Thanagar and Asgard were engaged in low but protracted skirmishes across the cosmos, effectively slowing the Asgardian expansionism spearheaded by Odin. With the return of the Demiurge, Odin was able to commune with the Fates and learn the horrible truth of their part in the Ragnarok cycle.
In 1500 BCE the last skirmishes of contested space were fought. A Thanagarian scout ship crashed to earth near the lands of Prince Khufu. From the wreckage he salvaged Nth-metal tools and machines that made him a formidable protector of his people. Sporadic visits aside, it would be some 3,500 years before Thanagar would return to Earth: this time, as part of the Alien Alliance Invasion.