Responses
We'll like in the middle ages, which all fantasy worlds are kind of based on had a average life expectancy of around 30-40. If we assume this world is a bit better, for example better hygiene, maybe it is around 60-70???? If this is the case, then he is a bit older but still he isn't a grampa hahahahaah
He retired soon after the title so probs didn't interact with all that many people after getting it and he did say he travelled around a lot so probs that's why.
But aye, just my guesses
Why is everyone treating him like an old man??? He's freaking 40 And why tf is it treated like it's so outrageous for a 40 year old man to have a disciple, like what??? Does everyone die young in this world to the point anyone past 35 is ancient?
And he has the official title of Sage, how come more people don't know about him?????