[quote=Svenn]
Are there other roles?
[/quote]

Y'all can structure your team and such however, if you have a title that the majority of your group acknowledges you having, then NPCs will acknowledge it as well, but leader is the only title I can think of that will have special metagame advantages. Rules-wise I'm not forcing you all to take titles of create an infrastructure/government for your group, but the more flavor/roleplay you mix in to the game the more fun it'll be.