"Souls bound to the Wheel of Life, Death and Rebirth" (quoted from the Everlasting, Book of the Spirits, page 252, © 1997-98 by Steven C. Brown)

Unfortunately the fifth book has not yet come out, so I do not know what Steve's intentions are with the Osirians. At this point they will simply be a part of the background for any games taking place from this web site. However these beings are truly Everlasting, as when they die, they return to earth in a new body after a short time, and as their new body develops they begin to remember parts of their previous lives (often by the time they are in their late teens or early in adulthood, sometimes even earlier in life). They are reincarnated people with amazing magical powers, Wizards or Mages if you prefer, who are reincarnated as the wheel of time spins through eternity.