Paizo's Horror Adventures introduces the interesting concept of disease templates.

Dr. Eric Lis is a physician, gamer, and author of the Skirmisher Publishing LLC sourcebook, Insults & Injuries.

A little bit more than a month ago, Paizo released Horror Adventures, which to me read a bit like Pathfinder’s lower-budget response to Ravenloft. It’s not a bad book by any means, and it definitely had some elements that I thought were quite clever. Among its other innovations was the interesting concepts of disease templates. Templates were one of the things that helped 3^rd edition D&D catch on, since they provided a way to take existing creatures and make them just different enough to keep players on their toes, and the writers for Pathfinder have had a knack for applying the idea of templates to a wider array of game mechanics. I actually really liked their idea of creating templates for diseases and, in retrospect, I was a bit surprised that I’d never seen the idea before.

Real-world diseases could often be described by templates, if you think about it. Consider, for example, the flu, influenza. On its own, the flu is a fairly common, not necessarily that frightening illness. Yes, it can knock an otherwise young and healthy person off of their feet for a few days, and it can make someone absolutely wish they were dead. A flu outbreak can even be expected to rack up a bit of a bodycount, and flu will inevitably be the cause of death of some elderly or people with chronic diseases every year, even in societies with the most advanced medicine known to modern humanity, let alone a medieval society. We understand the flu, and we can manage it fairly well. On the other hand, every few years, a particularly deadly strain of the flu pops up. In the 21^st century, we’ve some scares, but we haven’t really had a “superflu” the way people have occasionally feared. In contrast, there was the famous 1918 flu pandemic. During that pandemic, the famous H1N1 form of the virus rapidly spread all over the world and killed an estimated 500 million people (to put that in terms a gamer would understand, that’s about 5% of the world’s population, or, if you handed every single person in the world a d20 and told them to take one Fortitude save, every person who rolled a 1). The 1918 pandemic was particularly terrifying in that the disease seemed almost preferentially to kill the young and healthy rather than the old and infirm. It took us almost a hundred years to explain why that might have been the case; as fun as it might be, I’m not going to try to explain the concept of “cytokine storm” here, but suffice it to say that the virus probably hyperactivated the immune system so that it started accidentally shutting down the body, and better immune systems did a better job of shutting down organs. Quite a number of illnesses damage the body, not by themselves, but by triggering dysregulated immune responses, so this isn’t so unusual, but the speed with which it spread and the efficiency with which it killed was shocking and hasn’t been matched since.

In a sense, the 1918 pandemic can be thought of as a regular influenza with a template added. We could argue back and forth about which template it might have been. Out of the templates presented in Horror Adventures, this flu might have been “lethal” (extra deadly), “plague” (spreads especially efficiently), or “virulent” (fast-acting and dealing more Constitution damage per save). Quite likely, the 1918 outbreak would have had more than one of these templates, since it spread unusually efficiently and dealt more damage than expected, and probably had a higher save DC as well. Of course, if you wanted to get really specific, the 1918 flu would have required some templates not featured in Horror Adventures, which I might give names such as “slays the strong” (deals Constitution damage on successful saves instead of failed saves) or “shifts attacks” (after being successfully fought off once, recurs a few weeks or months later dealing damage to a different ability score). It doesn’t take much imagination to see how diseases with templates like these can destabilize an entire world, just as the 1918 pandemic shook ours. Add on another Horror Adventures template, such as “incurable” or “magic-resistant,” and you do indeed have the makings of a horror story.