Carnelian's story is not only about being slave and sitting in his master's palace)

One day he got some kind of curse and that's what happened next - he started to change. Once at months he loses his mind and became more animal than intelligent being. His skin itches and darkens, horns and spikes grows at his head, back, elbows etc. He becomes very hungry, but food does not help to satisfy this hunger. Cursed one needs something else but have no idea, what exactly.
This becomes worse and worse and in the end Carnelian turn into an mad, hungry berserker. Only thing which can calm him down and turn all changes back is fresh blood.

This is not the vampire or werewolf curse (but it similar to both at some sides), and one day i'll tell more about that strange disease) This is important part of world lore for me and i really like ewerything abouy this curse - it's hunger for blood, uncontrollable transformations and of course - curse's creator.