Uthera Midgeerrd

Uthera Midgeerrd, known more simply as Uthera, was a Forerunner-controlled planet at the edge of Ecumenical space. At some point between 100,300 BC and 100,000 BC the planet was completely overrun by Flood.

History
Little is known about the planet, except that which can be gleaned from pre-existing dates. The planet was first settled by Forerunners prior to 110,000 BC, according to the Promethean, Sharp-by-Striking, as a military outpost on the edge of Forerunner-controlled space. By 100,300 BC the planet had at least one large city on its surface. Some time after the return of the Flood to the galaxy, they reached Uthera and swiftly consumed all life on the planet. By the time the wreck of a Builder ship carrying the Ur-Didact and several other sentenced Forerunners arrived in-system, there existed a massive spore mountain where the city once lay. There was also a Precursor anomaly in apparent orbit around the infested planet. This would be the first of many Precursor artifacts to be used by the Flood against the Forerunners during the war. The planet was purged of all Flood ca. 100,000 BC when the Halos were fired.

Trivia

 * While this is conjecture, it is possible that the star system is Midgeerrd and the planet itself is Uthera. This can be seen in the First Human Empire, with planets such as Charum Hakkor and Faun Hakkor, where Hakkor is the system and Charum/Faun is the planet.