DM-3-1123 b[1] was a planet in the DM-3-1123 System and had a population of approximately 1.3 billion Forerunners.


A Forerunner naval group engaged a Flood irregular naval group of 149 non-military vessels over DM-3-1123 b, destroying the contaminated vessels. But the Flood's sole intention was to infest the planet, and within 32 hours they had overrun local Forerunner ground forces. Only 0.0006% of the planetary population was successfully evacuated (about 7,800 individuals out of 1.3 billion) before the Forerunner local fleet—upon an 83% consensus—launched a "blanket orbital bombardment" of DM-3-1123 b, destroying the Flood infestation but rendering the planet uninhabitable and sacrificing much of the planetary population.