What's the RPG where one character class acts as a “conduit” or “catalyst” for the others' “spells”?

Question

I'm looking for the identity of an RPG I remember reading in paperback book form (rather a thick tome), must have been published late 80s–early 90s.

A distinguishing feature was that while many (or in fact nearly all?) character “classes”* had specific magical/psionic abilities, they all depended on a further class of characters whose only role was to “enable” aforementioned “casters”. I think the enablers were called conduits or catalysts.

^{* Please excuse the heavy use of quote marks. I'm not sure of the exact terminology and I remember that the background actually avoided typical fantasy/sci-fi nomenclature (maybe that's another distinguisher if I remember rightly!)}

Answer 1

I do not remember an RPG built on it, but this definitely sounds like the Darksword saga to me.

After some search, perhaps I found the game you remember: Darksword Adventures.

Unusually, a game in the format of a paperback novel. Darksword Adventures shares a setting with the four Darksword books by the same authors. It is a fantasy setting where magic is Life and those without it are outcasts. Your status in the world is strictly determined by the nature and power of your magic.