Regrowing Pains

Eric Lis
Regeneration is a huge word in modern medicine. In a number of medical specialties, regeneration is imagined to be the next huge step that we're going to take. Currently, medical science lacks the ability to take a bunch of cells -- be they regular old skin cells or the totipotent stem cells -- and reliably persuade them to rebuild missing tissue. A handful of body parts seem to be capable of true regeneration, meaning, regrowing large volumes of lost tissue in a predictable fashion, without turning into either non-functional scar tissue or unregulated cancerous tissue. The liver has some regenerative capacity beyond that of most parts of the body, and more and more research is suggesting that there's regeneration of the brain in some situations. By and large, though, the body doesn't regenerate, and that's just one of the many reasons why health care in a medieval fantasy setting often seems a lot more attractive than what we've got on Earth.
How does the Regenerate spell work, though? Or, to put it another way, how is it guided? Regenerate is often thought of as a sort of fire-and-forget spell: the cleric casts it and then goes off to do something else, confident that the right things will regenerate in the right way. The vast majority of the time, that's presumably a safe assumption. Let's say that the party fighter got into a melee with something a few challenge ratings higher than himself and got his arm cut off. We assume that this fighter has never had any other meaningful injuries in his life that went without magical healing, so the only possible wound which he can regenerate is his severed arm. Simple, right? Maybe a little too simple. Let's make it a little more complicated.
So, same situation: the fighter's down one arm and the cleric, being a nice sort of guy, is going to fix him. Now, though, let's give him a past medical history. It turns out that when you ask the fighter if he's ever been sick before, he tells you that last year, he had two days of absolutely terrible pain that started around his belly button and moved to his right lower abdomen. He doesn't remember what it was, but the local wise woman cut something out of him and he couldn't go adventuring for two weeks while his incision healed. Smart people that we are, we know that our fighter probably suffered a bout of appendicitis, so his appendix was taken out. Well, now we've got a question: when the cleric casts Regenerate, is the fighter's appendix going to grow back?
But, you say, in my campaign setting, nobody performs surgery for appendicitis. If that's the case, then for some reason, you aren't using Insults & Injuries, which I find strange and inexplicable, but let's forget about that for the moment. Either way, the fighter's never had surgery... lucky man! Has he ever lost any teeth? If so, are they going to regenerate too? Has he started going bald, and if so, will Regenerate make his hair start to grow back? Has he started needing reading glasses, and if so what will Regenerate do to his eyes? And hey, when did he last shave, anyway?
There's no single answer to these questions. I have my answers, of course, which are complicated and not necessarily logical, but for your campaign, these are questions which only the storyteller can really answer (ideally, with some input from the party healer as to how they want their magic to work). Should Regenerate repair every wound that a creature has, even if this somehow harms them, or is Regenerate somehow guided, consciously or unconsciously, by the caster (or the recipient)? Some careful thought about this can really give a storyteller some interesting ideas to play with in a campaign.

More than four years ago, Dr. Eris Lis, M.D., began writing a series of brilliant and informative posts on RPGs through the eyes of a medical professional, and this is the one that appeared here on December 7, 2013. Lis is a physician, gamer, and author of the Skirmisher Publishing LLC OGL sourcebook Insults & Injuries, which is also available for the Pathfinder RPG system