Xandar is the home planet of the Nova Corps.
Xandar is the home of Xandarians, but also of many other species. The Kree accuser, Ronan wants to destroy Xandar due to an ancient war between Xandar and the Kree Empire. Ronan using the power of the Orb almost manages destroy Xandar but due to the intervention of the Guardians this did not happen. Star-Lord, along with the other Guardians, defeated Ronan, causing the peace in Xandar.