I forget which episode it is, but at one point Shun and his friends were talking about ways to acquire the Hero title. Since this is supposed to be a one-of-a-kind title only held by one person at a time, I was quite confused by the conversation.
I still haven't gone back to find the episode, but I don't feel that's necessary; with all likelihood, what they were actually talking about was the Hero skill, not the title, and I merely got confused. From volume 5 page 115 of the light novels:
The Demon Lord and Hero skills can be gained only by either using a huge amount of skill points or building up enough proficiency.
And it is further confirmed a character in Shun's party has this skill:
But for the Hero skill, it's said that you can gain it by behaving in a way befitting of a hero.
Hyrince, for example, gained the Hero skill through proficiency.