It’s a classic device in fantasy writing that a mentor will educate the hero or help them along in their journey.
Partly it’s an excuse to explain to the reader the rules of the magic system or society. It’s conveniently feeding them, at the same time as the protagonist, bite-sized pieces of information.
It also dovetails nicely with the protagonist’s character arc, developing competency and knowledge. The mentor teaches, and then stands back and watches, offering correction as best they can. Eventually, the mentor leaves – or is killed – and the protagonist must survive on their own, to show how capable they have become.
In The Lord of the Rings, Gandalf is a mentor-archetype. It is he who explains to Frodo the urgency of the mission and points him in the right direction. Gandalf helps to construct the fellowship, leads it and finally protects it when confronting the Balrog. While in some respects Gandalf is hands-off (frequently disappearing on side missions), he’s also a super-mentor. He pretty much knows everything and can be trusted to do the right thing. I don’t think I can remember him having a weakness or character flaw?
I really like what Patrick Rothfuss has done in The Name of the Wind. The lead character Kvothe is a child among the Edema Ruh, travelling performers of great repute with an eclectic mix of talent. After a tragedy befalls them, he lives alone in the forest for the summer, and then becomes homeless for many years in a crowded city. Circumstances occur so he can join the University he’s dreamed about as a child.
Kvothe’s vast range of experience, and the various mentors he’s had in life, enable him to believably possess a wide repertoire of skills. It’s a clever move by Rothfuss – putting him in such environments and contexts.
It is an epic-length read, but I’m greatly enjoying the book. Rothfuss has a great way with words, and I suspect I’ll be forced to read the entire series.