In Battlefront 2 the hero units unlike most other units take permanent damage as well as temporary damage when hurt. In this manner it appears to be possible to eventually kill any hero, if at least a small amount of damage can be done to them. But its not totally clear how this mechanic functions. Does half of any damage become permanent, more or less?

I assume damage taken while under a hit point buff will not be permanent until the buff is totally consumed.

What percentage of data becomes permanent?

Is it different for different heroes or does it work the same way for all heroes and for all types of damage?