The Fellowship of the Ring by Glorfindel

I believe it is a direct Tolkien reference rather than like a pastiche toky. Glorfindel needs her help at one point in the book, opening a door on all Hallows Eve so that dead spirits can go to wherever it is they go. She knows that that's not actually his name. He doesn't have a name. And there's one or two other things like that in the book where he's like, Hey, need you to do a thing and she kind of has to figure out how to do it and whether or not she wants to do it. But it's not like she has to learn to be a magician to get through the world and overcome some evil