[@Reflection]  Not necessarily. For instance, let's say that a servant with a strong resistance to magic were to kill Cain with some kind of magical attack. The opposing servant could theoretically survive the attack because their resistance to it would be leagues better than Cains. I suppose given his low luck stat someone could also survive through sheer luck. Obviously any NPs that alter fate or something of that nature would work as well. There are probably a few other ways to get around his NP, maybe really powerful healing or something, but typically Cain's weakness would lie in his opponent being more durable than he is.