Jul 'Mdama was a radical and ruthless Sangheili warlord, and a leader of the alien empire known as the Covenant. 'Mdama was a warrior who served the Covenant on the battlefield during the War of Trespass, as well as The Boss Cass War. 'Mdama built up intense hatred for humanity because of the doctrine of the Covenant which claimed that all humans were impure and an affront to their religion. This combined with the fact that they killed many of his comrades during the many conflicts between Earth and the Covenant.

Jul 'Mdama struck at Earth in the mid 2100's, during the time of Blue Team. He discovered the location of an ancient Forerunner weapon, the Composer, which he greatly sought to acquire. In his brashness, Jul 'Mdama waged war on humanity in the name of his gods. This time, he met his end during the final siege of Earth. He intended to fire a death ray from the Composer upon the planet to exterminate all humans, but he was defeated by Lord Vilgax before he could fire it. His body was later flung out into space, forever lost (possibly).