For my new world of Onaviu, there is only one realm: Power.
To be wholly honest, I have gotten tired of multiple realms. Yes, multiple realms definitely adds some flavor, but I think it is too much. Kind of like putting in a tablespoon of pepper when you only need a teaspoon.
For Onaviu, there are multiple forms of Power, but it all still comes from only one realm, regardless of the type. Just because there is only one realm of power does not mean a power user could not still be a Cleric, or a Healer, or an Illusionist, or a Scribe Master, or Crystal Master, etc. S/He simply focused their learning of the power into such spells.
See this thread for some development on Onaviu:
http://www.ironcrown.com/ICEforums/index.php?topic=11723.0
Even the psionics from Spacemaster are still from the same realm as what could be called magic on Onaviu. The mechanics may be slightly different, but all power draws from just the one realm.
rmfr
P.S. - Yes, I know they are called psychic powers in SM, but I prefer psionics. Yes, I know WotC has that in D&D, but the word psionics is actually decades older than D&D. I think Arthur C. Clarke used in it one of his novels in 50s. Or some other Golden Age author.