Way back in March of 2012, a friend of mine posted about Wise Guys— the old man who accompanies the hero on his journey and provides justifiable infodumps. She makes good points: this guy is overused, he is most common in the fantasy genre, and you should probably avoid him if you value your originality. I agree… to a point.
Most fantasy books are milieu stories. Since the author has spent so long creating this world for her characters to live in, she can’t help but write about it all. Placing plot points in exotic locations, she gives a tour to the reader. Unfortunately, if the main character knows all about everything already, she can’t make him curious enough to give the reader the necessary information. The character would just brush off all explanations, knowing it already. Instead, the main character is someone new to this world, often with approximately the same grounding in reality as the reader.
Since the main character is new to the world, just as the reader is, they need someone to explain the world to them. Why does this place lack technology? What’s the history? Why do all the short people have hairy feet?
Thus Gandalf was born. Thus Obi-Wan Kenobi was born. Thus a trope was born.
Nowadays, everyone uses this. Going from a familiar world to a strange one, the clueless main character needs a guide, so they get their own personalized Gandalf. But because everyone does this, it’s labeled as unoriginal, cliched, unwanted.
These people are talking themselves out of success.
This cliche has only survived because it works. It works too well, which is why it’s a cliche. But it being a cliche is no reason to write it off altogether. This thing works, whether you like it or not. It’s better than infodumping. It’s better than nothing. And since this guy usually saves the main character once or twice during the stages of his training, he’s almost necessary if you want to keep up a realistic try-fail cycle without letting the character die before he succeeds. However, you do not want to dress this guy in grey or brown robes and give him a long, white beard. That would be considered more cliche and unoriginal than the character himself. Instead, look at what the character does for the story and try to fit that into another, more interesting character.
For instance, Gandalf. Gandalf is the original wise mentor, but he is forever disappearing to mess with other events all over Middle Earth. He doesn’t have only one role (like, say, Obi-Wan, or Brom). However, his main role is that of Frodo’s informant and protector.
Usually, these mentors are old. Try throwing a young one in there instead. Perhaps you could give purpose to your love interest by making him/her the informant (Annabeth Chase). The best friend is an interesting version (Ron Weasley and Hermione Granger).
Usually, these mentors are single people. Give the job to two or more people (Ron and Hermione again).
Usually, these mentors like the main character. Make this guy antagonistic. (That’s what I’m going to do in Fathoming Egression.)
I think I’ve made my point. Sure, the wise guy is overused and cliche by now, but that doesn’t mean you can’t use him.