Allow healers to "burst" fallen people who are sharing them, but instead of a normal burst heal it instantly revives the person for X seconds. After that time is up, they die again, maybe retaining some of the damage they took while alive, making them harder to heal. They probably are only returned to a fraction of their health, maybe there would be an additional penalty if they died while this ability was active, but that probably isn't needed if we already penalize for damage taken. Healing received while the ability is active would work while the target is alive, but won't have any effect on how fallen they are (they will always return to their previous level of "fallenness", plus any additional penalty I feel is needed for balance/risk.)
I anticipate the ability largely being used instead of a chain for escapes, but I can imagine some other really cool uses. It's not uncommon for a very strong healer to be the last member of a group who is alive. That healer bursting up the most powerful fighter, and then healing another player while the fighter protects them sounds really exciting. I like the risk that the fighter in that case might end up unhealable as part of the last ditch gambit. I suppose on a routine hunt it could be used to burst weaker players for their last minute tags, which is significantly less exciting, but probably also fun for both the healer and the dead player who otherwise would have had to sit out the fight.
One great thing about this ability is Faustus, Sespus, and Horus can be important ranks. Some combination of Faustus and Sespus can determine how much the dead person is healed, and Horus could not only enable the ability to be used on people who are more fallen, but will be useful when raising fallens who take damage after this ability is used on them.
I'm not sure if it makes sense to make this ability trainable, my intuition is that it does, but maybe it needs a cap. For each rank to feel substantial I think it'd have to be pretty effective, but the ability has some natural caps (it probably doesn't make sense to go above 100% health, or stay alive more than some number of seconds). Or maybe it would end up being best as a consumable item primarily driven by existing stats. I'll probably start it off that way to test it out, that way I can play with balance without screwing up peoples training.