POPULATION: 12.5 billion
Doisac is a large, tropical planet, and the homeworld of the Jiralhanae. It experiences regular volcanic activity, and has a surface gravity more than twice that of Earth's. When the Covenant arrived in 2492, they discovered a planet experiencing a severe environmental catastrophe. Though sometime in the past the Jiralhanae had been a space-faring race, they managed to regress considerably due to global nuclear war known as the First Immolation. The Covenant took advantage of this, and accepted the Jiralhanae into their alliance, but placed them very low in the hierarchy. It was only the actions of the Prophet of Truth and the Great Schism that allowed the Jiralhanae to rise to near the top of the Covenant, albeit for a very short period of time.