The Yesodites were a posthuman group that modified themselves to live on Yesod. The ancestors of the Yesodites were the Malkuthites. (PROSE: The Long Midwinter) When they first came to Yesod, they destroyed all of its native life, including the Yesodi. (PROSE: The Long Midwinter, AUDIO: The Wake)
The Eighth Doctor, Samson Griffin, and Gemma Griffin once visited Yesod and met the Yesodites. (PROSE: The Long Midwinter)
Yesodites adapted to life in the City of the Saved by sealing themselves in personal vacuums. During the Civil War, Rex Halidom encountered a swarm of Yesodites and briefly chatted with one, Leremu Seed-of-Tiphereth. (PROSE: A Hundred Words from a Civil War)