Even for the same mentor spirit, that spirit might manifest itself in different ways in different traditions, or to different individuals. And people can have a variety of relationships with their mentor spirits - skeptical, trusting, struggling, cynical, etc. Consider how a mentor spirit interacts with a character, and how that character views his/her mentor spirit, when you make a character - but don't feel constrained to pigeonhole that character a certain way. That said, you should still keep the broad brush strokes of a mentor spirit in mind, and not deviate to the point that you are ignoring the major aspects of it.