Ephsu I

From Halopedia, the Halo wiki

Ephsu I
Zeta Halo


Ephsu system[1]

Orbital position:

First planet








"Not much around except that super hunk of rock out there blocking our target."

Ephsu I is the sole planetary body in the Ephsu system.[1] It is a massive, uninhabited terrestrial world that has an atmosphere and water present. The planet was most noteworthy for being the former anchor for Installation 07.[2]


Anchor for Installation 07[edit]

Following the orders for the IsoDidact, Installation 07 was sent to an unspecified system, where, according to Chakas, the ring "became a sacred tomb for millions, though some may still live."[3] Installation 07 eventually received its final activation preparations,[4] and fired after the other six Halo rings in 97,445 BCE.[5][6] However, following the array's firing and the process of reseeding the galaxy with intelligent life had begun, an uncatalogued species called the Xalanyn were discovered to have mysteriously survived.[7] At the behest of the remaining Forerunner council, Installation 07 was moved to the Ephsu system so that it would be in close proximity to the Xalanyn's homeworld.[8][9] After a parley between the two species, the Xalanyn were imprisoned on Installation 07,[10] which remained in orbit over Ephsu I.[9][1][Note 1]

As of late August 2558,[11][Note 2] Installation 07 stood at a distance of fewer than 12,000 kilometers from the planet.[1]

Battle for Zeta Halo[edit]

In December 2559, during the Battle for Zeta Halo, Zeta Halo was rocked by a cataclysmic explosion. Shortly thereafter, it was suddenly moved from in orbit around Ephsu I to an unknown location in space by Cortana.[12][2]


List of appearances[edit]


  1. ^ When Rion Forge visited Installation 07 in 2558, she was confused by its position over Ephsu I. Understanding that the Forerunners typically endeavored to position the rings around gas giants so that societies would not form in the shadow of the ring and to avoid it luring in potential settlers, she surmised that, given the circumstances in which the Halos had been dispersed and fired, the Forerunners had simply run out of time to find a gas giant to anchor it in a suitable firing position, or that one simply did not exist in the sector. However, she was simply unaware that Installation 07 had moved from its original firing position to the orbit of Ephsu I.
  2. ^ Chapter 1 states that it happens in August, and it was three weeks prior to the events in the prologue, which takes place in orbit. Given no date change listed in the chapter heading, it is most likely approaching the end of August.


  1. ^ a b c d e Halo: Point of Light, chapter 8
  2. ^ a b Halo Infinite
  3. ^ Halo: Primordium, chapter 42
  4. ^ Halo: Silentium, String 36
  5. ^ Halo: Silentium, String 38
  6. ^ Halo Encyclopedia (2022 edition), page 350
  7. ^ Halo Infinite, Banished Audio log: Archaeological Findings #03 - Xalanyn
  8. ^ Halo Infinite, Audio log (Halo Infinite)#Archaeological Findings 2: Archaeological Findings #04 - A Curious Directive
  9. ^ a b Halo Waypoint, Canon Fodder - Ship Strike (Retrieved on Apr 22, 2023) [archive]
  10. ^ Halo Infinite, campaign mission Endless: Silent Auditorium
  11. ^ Halo: Point of Light, chapter 1
  12. ^ Halo: The Rubicon Protocol, page 258