TheLibrarian
Explorer
I define adventurers as: People who, for whatever reason, have a vested interest in the adventure. They have some kind of tie to the story events that are happening. They receive some kind of "call" to the adventure and they have a set of skills that can help shape events moving forward. They are also often part of some kind of social group (even if loosely).
For instance, in my current Ravenloft game, all the characters have some kind of tie to Van Richten. Their call to adventure is that he's in trouble and they have a set of skills (having been trained and mentored by him) that can save him.
In another campaign, the heroes were all members of the same town that was being increasingly harassed by the fae.
Group cohesion is more important for me than classes or skill because I never just random people setting off to do some stuff. (I've used Fear the Boot's Group Template to help flesh this out in the past.) In addition to giving the characters a reason to be together and to care, it helps organize the players.
For instance, in my current Ravenloft game, all the characters have some kind of tie to Van Richten. Their call to adventure is that he's in trouble and they have a set of skills (having been trained and mentored by him) that can save him.
In another campaign, the heroes were all members of the same town that was being increasingly harassed by the fae.
Group cohesion is more important for me than classes or skill because I never just random people setting off to do some stuff. (I've used Fear the Boot's Group Template to help flesh this out in the past.) In addition to giving the characters a reason to be together and to care, it helps organize the players.