Someone alluded our Kingslayer to Luke Skywalker, which is quite fitting. Another possible inspiration for his story is Tyr, the norse god of war. Needless to say he is a great swordsman. But where it really gets interesting is the legend of the leashing of the Fenris wolf. For those unfamiliar with norse mythology, the Fenris wolf is one of Loki's (the trickster god) children, a huge wolf - prophetised to devour the moon at Ragnarok - the end of the world. This beast of a wolf wouldn't let the gods put this leash on him, so they had to trick him. They taunted the wolf and finally he agreed to be leashed if one of the gods put his right hand into the wolf's mouth - to prevent any treachery. Needless to say, it was the brave Tyr that stepped forward - and subsequently lost his hand. Now, as for Golden Boy Lannister - the reason that Cat sets him free is to free the wolf girls - which might be counterintuitive. But when he strays from the path that Cat set him upon - that is, when he tries to break free from Brienne. Well, that's when he looses his hand. For his treachery against the wolf.
