Stay safe !
In Casca's case, no matter how badly he gets wounded, he heals. He literally cannot be killed. of course, there's side effects, too. One is, he feels the pain of a wound TWICE, once when it occurs, and then a second time, equally, when it heals. He is unable to sire children, as well, and his blood will kill anything touching it.
He's even survived, at GREAT pain, being burned at the stake.
Being cursed by Christ on Golgotha apparently ain'tno joke.