For my campaign there is an option at higher levels to take a blood transfusion with a half orc half hobgoblin and I want the creature to take damage if they aren't either of those races, what damage type would that be?
closed as primarily opinion-based by enkryptor, NautArch, Miniman, Purple Monkey, Tiggerous Mar 29 at 12:20
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.
Use rules for poison or disease
All possible damage types in 5e are:
The closest thing to the case you're describing is a disease. Diseases normally deal poison or necrotic damage. The precise amount depends on how severe this condition is, therefore, is totally up to you as the DM.
You can use poison rules for any suitable poison from DMG as inspiration. An example:
A creature subjected to this poison must make a DC 10 Constitution saving throw. On a failed save, it takes 6 (1d12) poison damage and is Poisoned for 24 hours.
Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.