Year 20X5, in the Cosmic Calendar, was the year in which the Space Research Vessel Marina was attacked by the Space Pirates. The ship had been returning to Galactic Federation with samples of a newly discovered life-form before it was attacked. This life-form was called the Metroid, and it was discovered to have parasitic traits, including the ability to siphon the life energy of any living organism, leaving nothing but a brittle husk. The Space Pirates, desiring to use the Metroids as bioweapons, seized the creatures and made haste for their stronghold on planet Zebes, where they began to clone the Metroids by exposing them to beta rays. The Galactic Federation located the base, Tourian, but was unable to seize it. They sent in legendary Bounty Hunter Samus Aran to Zebes to destroy the Metroids, in what would be called her Zero Mission.

Metroid and Metroid: Zero Mission are set in 20X5. From there, the official in-universe timeline of the Metroid series is inconsistent. Also compounding the timeline is the introduction of cycles in the Prime Series as an alternative method of measuring time.

  • Unused narration in Metroid Prime states that the game takes place ten years after the original Metroid. However, because this narration was cut from the final game, it is not considered canon.
  • The Metroid Prime comic states that the game takes place two years after Samus's mission to Zebes. However, due to numerous inconsistencies (including the fact that the aforementioned mission to Zebes is implied to be her second mission), this is not considered canon either.
  • The Metroid Prime Trilogy art booklet states that Metroid Prime takes place three years after Metroid: Zero Mission, but the placement of most of the following games is not clear.
  • Metroid Prime: Federation Force has a contradictory placement in the timeline; while it takes place after Metroid Prime 3: Corruption, it is also said to occur in Year 20X6, which would be a year after Metroid: Zero Mission.
  • The SR388 Data File trailer for Samus Returns says that it takes place "less than a year" after Zero Mission.
  • In Japanese commercials for Super Metroid, Samus states the year to be 20X7, two years after the original Metroid. This also means Metroid II: Return of Samus and Metroid: Samus Returns are set in 20X7, as Super Metroid takes place shortly after Samus Returns.
  • The Prima's Official Stategy Guide for Metroid Fusion states that it "has been eight years since" Super Metroid. Since a specific year is not mentioned, this neither supports nor contradicts any other depiction of the in-universe timeline. However, it could just as easily be referring to the out-of-universe time between the releases of Super Metroid (1994) and Fusion (2002).

Related manual quotesEdit

"It is now year 20X5 of the history of the cosmos, and something terrible has happened. Space pirates have attacked a deep-space research spaceship and seized a capsule containing an unknown life-form that had just been discovered on Planet SR388."
Metroid II: Return of Samus
"Samus' greatest achievement has been the destruction of the pirates' Metroid plans on the planet Zebes. In the year 20X5 of the cosmos, an unknown life-form was discovered on planet SR388 by a Galactic Federation deep-space research ship."
Metroid Fusion
"In Cosmic year 20X5, a Galactic Federation exploration vessel discovered an unknown organism on SR388. The hovering creature was a Metroid, an entity that exhibited frightening parasitic, energy-absorbing properties."
Metroid: Zero Mission
"In the year 20X5 of the Cosmic Calendar, a terrible incident occurred. The Space Pirates attacked a deep-space research vessel and seized capsules containing samples of an unknown species that had been discovered on planet SR388."
Metroid Prime Trilogy
"Cosmo Dating System, Year 20X5, Galactic Federation exploratory vessel was attacked and destroyed by Space Pirates which transporting an unknown life form that was captures[sic] on SR388. The Metroid was taken to a stronghold on the planet Zebes."
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