[@Saltwater Thief]We actually discussed this a little in our GM PM a while back. Didn't decidw on a ything, but one way we looked as a trade off kind of thing, where a healer could heal someone at the cost of weakening their prana shield. 

An idea for your character is that it coukd have a sinilkar affect to Spell Resistance in DnD, where the barrier needs to be lowered entirely. Ir could alao be that you have to weaken the prana shield of the other person a certain amount in order to heal, and break it completely to disintegrate fools, which can be done. The Prana inside peeps is what keeps, lets say Kotori, from xutting all your arteries up because of Prana interference, while the actual barrier of excess Prana helps to protect you like Aura from Rwby, while alao seev ing as a back up reserve(i think) for ability users to tap into if internal reserves get too low.

Grey probably can explain better and give an better idea, but I hope thisa helps a little.