The Ruach are a group of people that predate current residents of Temerant. They appear to have longer lifespans than the people who reside in Temerant during Kvothe's time, with notable members being Selitos, Lanre, Iax, Tehlu, Kirel, Deah, Enlas, Fair Geisa, Lecelte, and Ordal. 
Most of the Ruach hung back from Selitos, too. They were afraid, and they did not wish to become involved in great matters.
Ruach may be an earned title, and all human residents of Temerant may not have been Ruach, or Ruach could have been a general name for all people at that time.