I'm not completely familiar with them, since Casters don't usually handle them, and so my parents didn't usually talk about them aside from talking about their Blood Breed hunter friends preventing some quarantines from going too badly, but... I've heard they can shape and harden their blood into very long, very sharp claws.

I'm not sure if that's true of Blood Breeds from every world, though. It might just be mine, so it might be better to take it with a grain of salt.