A noun for a “storyteller, composer of nyarnar or long epic tales” in Quenya Notes (QN) from 1957, a combination of nyarna “(epic) tale” and maitar “artist” (PE17/163).
Neo-Quenya: For purposes of Neo-Quenya, I would use this word for “author” as well.
nyarna noun "tale, saga" (NAR2), compounded in nyarmamaitar noun "storyteller" (PE17:163), literally *"tale-artist" (see maitar).