The Hydra System Massacres were a conflict that took place in the early years of human spaceflight.[1] It is very possible that they had to do with large groups of killings that occurred in the Hydra System. They most likely happened after the beginning of star colonization in 2362, but before the division of Inner and Outer Colonies was established[note 1] and certainly before 2518, when Halsey referred to them.[note 2]



  1. Based on Halsey's placement of them before the wars in the Outer Colonies, and after the Interplanetary War in Fall of Reach.
  2. Halsey's mention of them in Fall of Reach is dated August 17, 2517.


  1. Halo: The Fall of Reach - pages 20-21, Catherine Halsey: "Indeed, Lieutenant, ever since we left Earth's gravity well, we’ve been fighting one another for every cubic centimeter of vacuum - from Mars to the Jovian Moons to the Hydra System Massacres and on to the hundred brushfire wars in the Outer Colonies."
Community content is available under CC-BY-SA unless otherwise noted.