So, I figured I'd cover this before someone questioned it.
In Linnyanie-land, Clerics, Shaman, and Druids can resurrect (aka Rez). It's not guaranteed to rez their targeted corpse and the chance of success depends on the class, time of death and how often that person has died.
For example, a Cleric has a 75% chance of rezzing, while a Druid or Shaman have a 50% chance. If their targeted corpse has been dead for longer than 5-10 or so minutes, that chance lessens by about 25% (ie: cleric = 50% and druid / shaman = 25%). The chance of being rezzed is also lowered if someone has died a number of times recently.
So this is why Syned thinks Firefiend had died, despite the spell to resurrect being so common in healers, and this is why Firefiend keeps a Cleric around, specifically. Better chance to 'get better'.
This info is for Linnyanie-land, not Everquest or anything. I couldn't just make a story where everyone is incapable of dying, now could I?