Time mage?
Heals by reversing the damage dealt.
Could be a mix of Whm and Sch, by that i mean can grant weak shields and semi-potent regen but grants the unique abilty to "heal" TP and MP.
You may ask "how can this be edgy?", simple the job quests could involve some poor sod (black hair covering one eye is mandatory) trying to come to terms with rapidly ageing some one they cared about to death in some accident, this results in a person that pushes people away (yet somehow not you).

Simple, a edgy dark healer that kills people by rapidly ageing them. If Square soft let this pass i would be amazed.

~I'm a strong independent Black mage who don't need no mana~