Chi Rho was a UEG colony world in the Ectanus 45 system.


In 2535, during the Human-Covenant war, following the loss of most of the Outer Colonies, refugees had started flooding the planet and all available space was being used for victory gardens and refugee camps.[1] Vice Admiral Jean Mawikizi resolved to make a stand against the Covenant on Chi Rho, digging in deep within the planet's crust to survive a glassing attack, forcing the Covenant to come down and flush them out man-to-man.[2] Eventually the planet did come under attack.[3]

Physical AspectsEdit


Chi Rho had conditions very similar to Earth.[4] It is unknown if this is due to terraforming or if it Chi Rho naturally had these conditions.


Chi Rho has at least one moon, Eiro. It's tidally locked to Chi Rho.[5]


  • The name "Chi Rho" could be another biblical reference in Halo. The Catholic symbol of the letter X and letter P written as a single letter is called chi-rho. The symbol stands for the first two letters of Christ in Greek. It's also the reason Christmas can be abbreviated as Xmas.



  1. Halo: The Cole Protocol, Page 25
  2. Halo: The Cole Protocol, Page 31
  3. Halo: Fractures - Extraordinary Tales from the Halo Canon - Into the Fire, Page ??
  4. Halo: The Cole Protocol, Page 26
  5. Halo: Smoke and Shadow - Part One and Two, Page ??
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