In around 500 BC, a group of Xarkonian scientists discovered an enormous undergorund Prothean city on Xarko's moon, Ulic. The Xarkonians researched the technology and then mass-produced it, resulting in the Xarkonians joining the ranks of space-faring species in the Galaxy. When the Rachni Wars broke out, the Xarkonians offered to aid the Krogan in dealing with the threat. The Citadel Council allowed two Xarkonian armies to help the Krogans. The Xarkonian forces were instrumental in victory, being both numerous and vicious in battle. However, when the war was won, the Krogan received all the glory. Many Xakonians are still bitter about this today. Their thirst for vengeance was granted when the Citadel Council declared war on the Krogan. The Xarkonians amassed an army of literally billions