Eridanus II

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Eridanus II


Eridanus system



Orbital position:

Second planet


One; Ehilend[1][2][3]



1.01 G


1 (N2, O2)

Surface temperature:

-18°C to 38°C (0.4°F to 100.4°F)



Human (Non-native)


510,000 (Post-war) [2]





Eridanus II is a human Outer Colony planet in the Eridanus system. The planet was mostly rural, devoid of pollution or crowding, and had climate-controlled weather.[6] It was famous for its beautiful landscapes and higher learning centers.[2] It was the location of the cities of Luxor and Elysium City, where John-117 grew up until he was abducted and sent into the SPARTAN-II program in 2517. Emile-A239 was from Luxor, born there in 2523.[7]


Topography and ecology[edit]

Eridanus II boasted vast territories free of pollution.[5]


Known residents[edit]


Rise of humanity[edit]

Eridanus II was settled in 2440.[4][5]


The secessionist rebels in the system staged a localized rebellion against the UNSC in 2494 and briefly took control of the planet.[8][9] The UNSC struck back two years later in Operation: CHARLEMAGNE and forced the rebels out at the cost of four destroyers.[10] A large number of rebels survived, however, and under the command of the UNSC turncoat Colonel Robert Watts, overthrew the civilian government of the system in 2513. Watts was presumed killed in the UNSC's counterattack, Operation: TREBUCHET, but in fact he escaped to Eridanus Secundus in the system's asteroid belt with the rest of the rebels.

In 2517, Dr. Catherine Halsey and Lieutenant Jacob Keyes visited the planet during the former's mission to observe the SPARTAN-II candidates. Halsey met John-117 at a playground in Elysium City's Education Facility 119, where she determined his admission into the program with the flip of an antique coin.[11]

As part of Operation: TREBUCHET in 2524, Colonial Military Authority Marines attempted to raid an Insurrectionist base on Teribus Island. Sympathizers in the unit tipped the Insurrectionists off, and by the time the dropship arrived it had been abandoned. Later, a nightclub in Elysium City was targeted by Insurrectionist bombers because it was a favorite CMA area for off-duty personnel, killing dozens of civilians and a CMA pilot, Allison Stark and putting a CMA Marine, Eric Santiago, into a coma. Gage Yevgenny and Felicia Sanderson were injured, but survived the attack.[12] Around this time, refugees from Eridanus II ended up in Pirth City on Arcadia and New Jerusalem.[13]

It remained a place of much hostility against the UNSC, and many pirates and rebels continued to operate across the system, with the asteroid belt as their main base of operations. John-117 returned to the system in 2525 with the other Spartan-IIs aboard the destroyer UNSC Pioneer for their first mission to capture the rebel leader, Colonel Robert Watts. The Spartan team boarded the cargo freighter Laden and traveled to the rebel asteroid base Eridanus Secundus, where they successfully captured the Colonel and escaped.

At an unknown time, a skirmish between UNSC and Insurrectionist forces during Operation: ROCK HOUSE took place.[14]

Human-Covenant War[edit]

Main article: Human-Covenant War

At some point during the Human-Covenant War, Operation: BLUE MOON took place on the planet.[15] Eridanus II was attacked and glassed by the Covenant in 2530 and the UNSC abandoned the planet.[16]


The planet was left largely intact, enabling rehab pioneers and original inhabitants to return hoping to rebuild.[5] By 2557, the UNSC had reclaimed and resettled the planet, as Nova Austin Station on the planet Cascade offered flights to Eridanus II that year.[17]

Government and society[edit]

The governing of Eridanus II was under the auspices of the Eridanus Government, an ally of the Unified Earth Government (UEG).[10] Eridanus II has some of the best educational facilities in the Outer Colonies.[5] Boxing was outlawed on the planet.[18]

Briefly, a group of rebels from the Secessionist Union took control of the planet.[8]


Children on Eridanus II, at some schools, can play gravball.[11]

Non-canon and dubious canon appearances[edit]

Silver Timeline[edit]

HTV-SilverTeam logo.png
This article contains information about the Silver Timeline, and is not a part of the established Halo canon.
Main article: Eridanus II/Silver

Originally uninhabited, Eridanus II was settled as a part of the Reach for Life project. The Reach for Life installation on Eridanus II was one of only six to survive its pilot stage, becoming a fertile forest built into an otherwise hostile planet. It was where John-117 was born and lived for the first several years of his life, at one point discovering a Forerunner keystone in a cavern near his home. His parents were the leaders of the Eridanus II colony.[19][20]


Eridanus (or Eridanos) is a river in Greek mythology, associated by Herodotus with the Po River.


List of appearances[edit]


  1. ^ Halo 3: Bestiarum
  2. ^ a b c Halo: Warfleet, page 22
  3. ^ Memory Agent, episode Chapter 4: Unsavory Means
  4. ^ a b Halo Encyclopedia (2022 edition), page 50
  5. ^ a b c d e Halo Encyclopedia (2022 edition), page 47
  6. ^ Halo: The Fall of Reach, page 22
  7. ^, Emile's profile page: (Quote)
  8. ^ a b Halo Mythos, page 55
  9. ^ Halo Waypoint, Colonel Watts (Retrieved on Apr 13, 2016) [archive]
  10. ^ a b Halo Encyclopedia (2009 edition), p. 44
  11. ^ a b Halo: The Fall of Reach, page 21-25 (2001)
  12. ^ Halo: Evolutions - Dirt
  13. ^ Hunt the Truth
  14. ^ Halo 5: Guardians Limited Edition, Dossier files - Frederic-104
  15. ^ Halo 5: Guardians Limited Edition, Dossier files - Linda-058
  16. ^ Halo: First Strike, page 240
  17. ^ Halo 4, multiplayer map Skyline
  18. ^ Hunt the Truth, Episode 03: CRITICAL CONDITION
  19. ^ Halo: The Television Series, episode Emergence
  20. ^ Halo: The Television Series, episode Homecoming