The Bard's Guild
Based in the elven city of Tylorus, where there is a long history of musical art, the Bard's Guild recruits those who can rise above the mere level of a minstrel, and use their voice to cause almost magical effects on those who hear their songs.
As well as the songs themselves, the guild teaches acrobatical skills, in order to help them perform and entertain crowds, or so the guild would have you know; Defending themselves in combat is the real reason they prize these abilities so much.
Finally, the guild teaches their members how to be inconspicuous, and while the bard is rarely suspected of wrong doing, some suspect the guild is actually some kind of spy organisation, gathering information as they perform.