The splash screen of Cetus.

Cetus is a city hub for the Ostrons, located to the north of Mantle, Earth. A humble settlement, located in the south region of the Plains of Eidolon, they are guided by a secretive order named The Quills, loyal to the ever-mysterious Unum.


Main article: Ostron

The Ostrons are the inhabitants of the Cetus settlement near the Plains of Eidolon on Earth. They are a hardy, mercantile people that dwell in the shadow of the Orokin Tower of the Unum, which they harvest for their livelihood. Kept safe from Grineer aggression by the arcane powers of the Unum herself, Cetus serves as their central trading hub in the Origin System and a refuge for all others who come to it with peaceful intentions.

The QuillsEdit

Main article: The Quills

The Quills are a mysterious monastic order that serve the equally enigmatic Unum, a being who resides within the Orokin Tower at Cetus in the Plains of Eidolon. They have very close ties to the Ostron people who also praise the Unum, and are seemingly knowledgeable about the secrets of the Tenno. They are said to be able to divine the future, which combined with their information gathering prowess allows them to preemptively end threats to Cetus through their operatives. The player will be able to ally with the Quills after completing both Saya's Vigil and The War Within quests and bringing their Operator to a cave in the north-east part of Cetus.

Plains of EidolonEdit

Main article: Plains of Eidolon

The Plains of Eidolon is an expansive, open Landscape located on Earth. In the shadow of the Orokin Tower of the Unum lies an ancient battlefield, where an enormous Sentient was defeated during the Old War. The Grineer have set up numerous outposts and bases to study and mine the ruins in the area, observing and patrolling the plains for any threat to their operations.


  • In the eastern part of city outskirts hides an Easter Egg in the form of the Digital Extremes logo, easily recognizable by its emblem. Activating it will show the credits roster for the Plains of Eidolon.
    • In the roster is Hayden Tenno, the main protagonist in Digital Extremes' previous game Dark Sector.
  • Cetus is the Latinized from of κῆτος (ketos), the Ancient Greek word for "sea monster". Cetus can also refer to a constellation of the same name.
    • Interestingly, one of the stars in the Cetus constellation is Tau Ceti, one of the closest stars to the Sun and is most likely the "Tau" system the Sentients were originally sent to colonize.


Patch HistoryEdit

Update 23.10
  • Added objective marker pointing players to Konzu when entering Cetus for the first time.
  • Added more Corpus and Fortuna npcs (undocumented).

Update 22.0

  • Introduced