In my world there are many small city-states without a centralized ruler. Armed conflicts break out often, due to subtle manipulation of a third party trying to encourage infighting; but no one knows that yet.
The world is somewhat medieval technology and limited magic (mostly weak alchemy and Healing). Healers are rare individuals born with the gift to heal someone by increasing the bodies natural healing speed, causing severe wounds to heal in a minute. Healers can only manage to heal a limited amount before they expand all their energy, maybe handful of wounded individuals for a new Healer. They also can only Heal the sort of injuries that a body could naturally heal with time. People who do not have the Healing gift, but are trained like regular doctors in first aid, surgery, and use of alchemical potions for healing are called medics. They can't manage the rapid recovery of Healers, but can help more people since they don't have to worry about using up all their Healing energy, and can treat injuries that can't be easily Healed.
The organization I mentioned is sworn to minimize suffering from the constant war. This group has a large number of trained Healers and medics, along with many able bodied folks that don't know medicine. They travel to battlegrounds to try to save lives. I'm currently calling them the 'corp' as a stand-in till I get a better name. This corp is well known and generally respected by the majority of the city states; and in particular the average soldiers and grunts adore them.
Most city states have sworn something called 'Edwards Oath', which is a sort of promise to support the corps humanitarian efforts. They swear to protect anyone working for the Corp, and to provide assistance to the corp 'when possible'. The most important part of the oath is the promise to not interfere with Corp members even when they are treating your enemies; so long as the corp provides equal assistance to your own side as well. This oath is important because this is a world where Healers are effective enough that they're usually the first targets in a battle.
Due to this policy the Corp has a very strong focus on neutrality. They try to always give equal amount of aid to both sides. They started out arriving at battlegrounds to treat the injured of both sides after the battle ended.
However, the Corp is going to expand to try to take a more active role. They are looking for more ways to take advantage of their unique role as both neutral, and protected culturally from being attacked, to find more ways to assist others.
One thing they are looking to do is start sending Healers to heal before the battle is over, on the grounds that they can Heal for far less energy if they get to someone immediately after they sustain a wound. The question here is how to do it safely. Sure it's effectively a war crime to interfere, much less intentionally harm, a Corp Healer, but in the middle of a chaotic battle mistakes happen.
I know any Healer sent into battle will be paired with one flag bearer, someone who's job is basically to shout "we're Corp, don't hurt us" to anyone that may interfere with the Healer, he would carry some obvious standard, and be trained in how to defend the healer (non-lethally) if he is attacked (one char has this job). However, what else would need to be done to keep them safe? What kind of negotiations would have to be made about when to send them in, how to avoid their being in the middle of arrow fire etc?
My other question, is what else could the corp do to minimize loss of life at a battleground? I already know they will have a dedicated diplomat that travels with them (another main character) who will try to negotiate to avoid battles from happening entirely; but often won't succeed (often the people at the battle don't have the authority to make that decision anyways, generals don't get to decide to end a war). She will try to get both sides to agree to terms before a battle as well, for instance they always try to get them to agree to send anyone saved by the Corp home instead of forcing them to fight in any more battles.
Are there other things the Corp could do, or other negotiated deals they could get two sides to agree to before battle, as part of their mission to preserve lives? The corps will likely have many non-healers, often soldiers whose lives they previously saved on hand. What uses could these Corp members serve?