It was said somewhere that Curses are connected to failed spells, so I'm not sure whether that's how casters learn them or whether there will be more.
And agreed, @MasonGamer, about the Sages. I think initially, if you bring a non-magical Sim who doesn't know any Spellcasters into the realm, the Sages are who can "turn them" (to use the Vampires word, since I don't know what it'll be yet in RoM). But afterwards, I'd be surprised if Casters didn't learn a way to make other Sims magic too, instead of having to bring them back to the realm every time.
