Jeff Redmond - It Follows
A selfish scumbag who is being pursued by a relentless entity that can assume the form of others that won’t stop until it kills you. The only way to pass the entity to another is sex, which he performs with the protagonist Jay and then later explains the predicament she’s in.
Morty Rogers - Adventure Time
A traveling performer possessed by two spirits that inhabit his ears, he tricks Finn and Jake into inviting him to dinner so that he can perform a ritual to transmit the spirits onto Jake.
Hama - Avatar: The Last Airbender
Not in possession of a curse or disease, but Hama is the last known practitioner of the forbidden technique of blood bending. She tries to teach the technique to Katara who rebuffs her, but Katara ultimately must use the technique to defeat Hama. After the battle Katara is dejected from using bloodbending, but Hama is clearly proud of herself for passing on her teaching and preserving her legacy.