Healers are your party's bread and butter, serving up healing to allies and asswhoopings to enemies.

Healer classes are
Monks
Priests
Shamen

they're your religious characters, stepping down from their temples and shrines to keep others alive. shamen are just doing what they're told by some unseen force. monks are generally happy to help, its a bit boring when most of your career involves blessing farms every time someone tills the dirt. and priests... well they'll help but the priestesses will jump at any moments notice to punish the wicked. (theyre crazy)