This article was first broadcast in Episode One Hundred Eleven on 18th March 2020.
Killer DM (drawn out and threatening): Oh Lennon…
Lennon: No!
Killer DM: No?
Lennon: Yes? What answer keeps me alive?
Killer DM: Oh we’re way past that point, but before I start showing you what your own spleen looks like, I was just curious why you tried to issue a notice saying Ryu shouldn’t be associating with me for the foreseeable future?
Lennon: Well…Ostron’s doing his research on infections and he recommended everyone avoid spending time in close proximity to other people…so…
Killer DM: So you decided now was a good time to attempt an underhanded ban on having me around. I can actually respect that; it has a deviousness I appreciate.
Lennon: It’s not a ban it’s just…you know…until Ostron’s done with his research.
Killer DM: Oh, that’s fine then.
(Loud pounding on a heavy door)
Ostron: What do you-ghaaah! Why-
Killer DM: Are you done with your research?
Ostron: Well I’ve got a few last things to tidy-
Killer DM: Are you done…with your research?
Ostron: Yeah, all set, ready to go.
Killer DM (with false enthusiasm): Wonderful! Let’s see what you have.
In a universe where instant cures and resurrections are a thing, one might think the threat of diseases has been completely eradicated in Dungeons & Dragons. However, in lore terms there are only so many clerics to go around. I mean, if you think about it, most of the time when the hapless adventurers wander into a town or village they’ve instantly become the most reliable source of medical care, which is a really sad state of affairs when you consider your average group of characters.
In game terms, while things like the flu or colds or even gangrene probably exist in D&D worlds, the basic rules don’t bother covering them. Sometimes they show up as plot points in adventures, where a village or section of a larger city will be cordoned off because of an unspecified plague, but most of the time those aren’t affecting the characters. However, that doesn’t mean there aren’t diseases and infections present in D&D that can cause problems for the adventuring party. They just tend to be well beyond the things the CDC would worry about.
We’ll start with one that transcends D&D; Lycanthropy. While various fiction sources, usually more modern ones, present lycanthropy as a disease, in D&D it actually exists as a curse, transmitted either genetically through parents or as the result of being wounded by a lycanthrope.
Mechanically the progression of lycanthropy is somewhat vague; if wounded, a character tries to resist the curse with a Constitution save against what is effectively the lycanthrope’s spell save DC using its Constitution. If failed, the character immediately begins suffering from lycanthropy, which is something they can either resist or embrace. The resistance or acceptance seems to be a pure roleplay decision and only dictates whether their character’s alignment changes and whether they have full control over shifting or if they resist it until a full moon, where the compulsion is unavoidable and they lose control.
Killer DM: So let me get this straight, your first item on research about infections isn’t even an infection? And you people wonder why I prefer ROSTRO.
Anyway, the next item on the list is vampirism. Classing this one as a disease is debatable too, but at least the remove curse spell doesn’t work as obviously here, but neither does detect poison and disease unless the DM feels like it, so if you want to make it a disease, that’s your call.
Transmission is pretty simple; get killed by a vampire. However that only gets you the discount version of vampirism where you rise again as a bloodthirsty chump basically enslaved to the vampire that eliminated you. Until you sample the hemoglobic vintage of your master vampire, you can’t be a free agent, and nothing fixes vampirism short of a wish spell.
Lennon: “Hemoglobic vintage?” How much time have you been spending with ROSTRO?
Killer DM: I’m giving you until the end of the segment at the moment. Do you want me to change my mind?
Lennon: I’ll just keep on reading then. Slowly…
5th edition does have a list of actual diseases that can afflict the players in the Dungeon Master’s Guide, beginning on page 256. The first one is called Cackle Fever, also known as “the shrieks.” Gnomes are for some reason immune, but anyone else infected with the disease manifests symptoms after 1d4 days, at which point they have a fever and disorientation, translated as a permanent level of exhaustion. On top of that, whenever the creature is under stress (like, from combat or dealing with confrontational work colleagues) they have to make a constitution saving throw or become incapacitated for 1 minute with a debilitating laughing fit.
Any creature not immune to the disease who goes within 10 feet of an infected creature has to make a constitution save to avoid becoming infected. Infected creatures make a constitution save after each long rest and, if passed, reduce the check to avoid the laughing fits by 1d6. Once they’ve reduced the DC of the check to 0, they’re cured. However, failing three saves forces a roll on the indefinite madness table.
Sewer Plague is the next disease on the list, although in the lore it’s a catch-all term for a number of different diseases originating from sewers and sewer animals (apparently the Forgotten Realms isn’t familiar with the germ theory of disease). The chronic symptoms are the same as Cackle fever where there’s a permanent level of exhaustion, but it adds on that creatures only recover half HP from spending hit dice, and they regain no hit points from a Long Rest. The creature also begins making Constitution saves after long rests, but rather than sinking into madness, this disease piles on levels of exhaustion every time there’s a failure, and reduces a level every time they pass. As soon as they get rid of the exhaustion, they get rid of the plague. Transmission occurs through bites or contact with bodily fluids of the infected.
The last disease listed in the DMG is Sight Rot, a lovely waterborne illness that causes a creature’s eyes to bleed continually. Fail a constitution save after coming in contact, and one day later the creature is bleeding from the eyes and has a -1 to any activity requiring sight, including attacks in combat. Each long rest the penalty increases by -1, until they hit -5, at which point they’re blind until someone with lesser restoration comes along. Healing this one requires someone with an herbalism kit and a specific flower, the rarity of which is determined by the DM.
Now, as is typical with 5th edition, these lists are meant to be permissive rather than proscriptive; Wizards wants you to take the basic diseases and play with them, changing the effects, incubation periods, or whatever to make them your own. So if you want, you can create a disease that has, say, a 14-day incubation period and has disadvantage on saves for characters over 40.
However, all of that sounds like work and we all know how I feel about that. So if you want more diseases to play with, my advice is to jump back an edition. I know, I know, 4th edition is about as popular as Mary at a Typhoid survivor’s reunion, but their take on diseases is kind of interesting. Each disease had 4 to 5 stages, numbered stage 0 through 3 or 4, and each had escalating conditions to ruin the characters’ day or eventually their life.
The mechanics have to be retranslated a bit, but it’s not hard. In 4th edition they made an Endurance check after each long rest, which you can turn into a Constitution save. Then there were two DCs, one higher and one lower. If the save was less than the lowest one, they progressed one stage up on the track. If it beat the lower but was below the higher, they stayed at the same stage. If they beat both, they decreased a stage. If they beat the higher save while at stage 0, they were cured. However, if they progressed to the highest stage (usually 3 or 4), the effects became permanent and had to be cured with magic or other special means.
Edition 3.5 also had a number of diseases that functioned similar to the ones in 5th edition, with a save made after each long rest to determine the effects of the diseases, but those can be more punishing because they began to directly affect and drain ability scores. Both the 4th and 3.5 edition diseases are accessible in online SRD resources if you don’t have copies of the books.
In all cases, the character’s save can be replaced with another character performing a medicine check. Usually the rules would allow either value to be used, but if DMs want to raise the stakes, they could enforce one or the other, or require that if one check is made after the other, the second result has to be used.
Now one additional note about these diseases; they’re based on how diseases really work, which means we’re talking about things happening over the course of days if not weeks. So if you’re running a stand alone one-shot it doesn’t make sense to give someone a disease that’s not going to show up for a few days, unless you need fuel for some sort of personal fantasy about one of the characters dying days later of explosive diarrhea. Make sure your campaign is at least taking place over a few weeks if you want to throw diseases in there, otherwise they’re just more pointless note-taking for you and the players. On the upside, more ways to put the characters in jeopardy!
Killer DM: Speaking of in jeopardy, that was it? Your research is done?
Ostron: Yes?
Lennon: No!
(violent spell sound, screaming, splat)
Killer DM: What!? Oh come on, that was an Oblex clone? Where is he?! I’m going to find him, then I’m going to find that overgrown jello mold!
Ostron: I have to say that was probably the best stealth check you’ve made to date.
Lennon: Yeah, well, between HR helping and getting Gath to Bless me before the whole thing I would hope so.
Ostron: How did you get the Oblex to help you out anyway?
Lennon: I…um…hang on, it’ll come to me.
Ostron: Yeah, I don’t think it will but anyway we should get over to the scrying pool so the Killer DM doesn’t find you and to give Ryu time to come back.
