Edit: Thanks to a suggestion from Kingreaper on EN World, I’ve edited the Intermediate State so that hit points can go up to the PC’s surge value rather than being capped at 1.
Two areas where I wish there were more official Dungeons and Dragons Fourth Edition content are traps and diseases. To help remedy that, I’m sharing a disease that I put together for my home game: Delirium Fever.
- Description: The patient is afflicted with a high fever accompanied by profuse sweating and weakness. As the disease progresses, the patient may fall into unconsciousness with periodic bouts of delirious wakefulness, babbling incoherently. Left untreated, Delirium Fever can be fatal.
- Level: 6
- Exposure: Via the venom of giant spiders (either at range via spitting, in melee via a bite, or after a hit from a weapon with spider venom on it)
- Progression: Saving throw to avoid infection after initial exposure. Endurance DC16 to maintain, Endurance DC 21 to improve.
- Initial state: The patient is weakened, and their hit points cannot go above their bloodied value (temporary hit points can still be gained as normal). Improvement from this state represents the disease being cured.
- Intermediate state: The patient is weakened and slowed, and their hit points cannot go above their healing surge value.
- Advanced state: The patient is unconscious, with occasional bouts of waking delirium.
- Final state: The patient dies.
In my game, the party encountered this disease when they ran into some duergar. The duergar use giant spiders as mounts, and the venom of these spiders exposes the target of the attack to delirium fever (based on a secondary attack against fortitude). The party came upon a mining camp where some NPC dwarves had been attacked underground by duergar. The survivors came down with delirium fever. The PCs went underground to rescue a dwarf prisoner and to try to get some spider venom in order to craft an antidote to the disease. In the process, one of the PCs ended up contracting the disease after a number of spider bites.
I was pretty happy with the role of the disease in my game, so feel free to use it in yours!