SHealth tied to something else - the health of a tree, the amount of frost on the ground, the inverse of another personâs, the political power of whoever cursed you
Curse of bad luck - makes any small illness or injury potentially fatal if not treated with anti-curse in addition to anti-infection procedures
Magical reliance on a magical or nonmagical substance - can have any number of side effects
Repeatedly being drunk by vampires can cause an increase in blood production and therefore high blood pressure and related ailments. Can be treated by blood letting.
Thereâs a lot of hybridization happening in a lot of fantasy settings, and thatâs just asking for a lot of people with weird half-dragon genetic disorders. Works out fine for some people, not so much for others.
Parasitized by (insert creature here). If you donât take the correct precautions to keep it dormant it will continue to spread and eventually hatch out/transform you.
Repeated contact with the undead has left you open to their influence - leading to hearing or seeing things that other mortals canât, which can distort or distract from more mundane concerns.
Alternately to being more vulnerable to intrusion, oneâs soul can form a scar that makes helpful magic more difficult to take in.
Sleep disorders that make one fall into an impenetrable sleep at a specific trigger, or to do so for years at a time.
Out of phase with 4D space, oneâs body not connected to itself or anchored in place/time in the usual way. There could be a consistent two hour gap between the things you hear and what has happened, you might clip into the floor as if it was in a different place for you, or you might slide through the material plane in cross section.
Intermittent intangibility.
Split into two people, each with only half your traits.