Dawn of the Old Gods: Tyranny of Dragons
Abyssal Plague Demons
The abyssal plague mutates those unfortunate enough to contract it. The fiend that you are mutated into has a large red crystalline shell. You develop long and sharp claws capable of slicing and infecting flesh.
The blood of these fiends is also highly familiar; being the red, gold speckled, liquid found within the numerous Voidharrow Basins across Faerun. These demons are dangerous even to seasoned adventurers.