Tier was a very large stepped habitat[1] located in the Lower Leaf Swirl of the Milky Way galaxy.[2] The habitat took its name from its shape.[3]

Tier was famous for its tightly interconnected multi-species society, a society which the habitat had been specifically designed to support.[3]


Tier was composed of nine levels. Levels were divided into compartments up to hundreds of kilometres long. The habitat's hollow axis was filled with mirrors and mirror fields to modulate and direct light into the compartments. Various planetary environments are recreated within the compartments.[3]

The habitat had at least eight levels. Level Three and Four featured one standard gravity.[4]

There were many facilities available in the c. 19th century CE. The View Hotel was located on Level Three, and the Night City was on Level Four.[4] The Ysner-mistretl racetrack was one level up from the level containing the embassy of the Homomdan Empire.[3] Elsewhere was an excellent Affront hunting reserve section.[4]


Tier was completed c. 51th century BCE. Its builders were believed to have Enfolded shortly afterwards, leaving the habitat in the care of the Tier Sintricates.[3]

The habitat did not send ships to investigate the Esperi Excession during the crisis in the c. 19th century CE.[4]; Culture and Affronter craft were requested to leave Tier during the associated and short-lived Affront-Culture War.[5]


The Tier Sintricates distrusted any entities that had less of a biological basis than themselves. The movements and communications of drones and machine intelligences were closely monitored. The avatars of Minds were met with outright hostility beyond the outer docks, where they were extended every hospitality. The discrimination was gladly tolerated given Tier's other superlative social attributes.[3]

Foreign relationsEdit

C. 19th century CE, Tier hosted embassies from the Elench[6] and the Homomdan Empire, as well as welcoming visitors from the Culture[1] and the Affronter polity.[7]


The Tier-sintricate-hour was a medium of exchange used on Tier; Ppyment was also accepted in equivalents.[8]


Ysner-mistretl races were held on Tier for millennia by the 19th century CE. The race track resembled a two-kilometre wide circular amphitheatre, with each level of seats rotating at different speeds.[3]

The habitat hosted the annual Festival of Tier, a themed event that drew foreign visitors.[9]


  1. 1.0 1.1 Excession, chapter 5.6
  2. Excession, chapter 5.2
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Excession, chapter 6.2
  4. 4.0 4.1 4.2 4.3 Excession, chapter 6.5
  5. Excession, chapter 8.4
  6. Excession, chapter 5.1
  7. Excession, chapter 5.5
  8. Excession, chapter 7.4
  9. Excession, chapter 3.4