@zeroxjac I understand your point with the sword, but that doesnt change the fact that this guy is portrayed as extremly curious about Abel, it doesnt make even the slightest sense for him to kill him. Abel is like the first person in years and years that interests him, he thinks of everyone else as boring, he doesnt want to kill him, he wants to know more. So, he clearly didnt send them to really kill Abel, even if it does look that way with the first attack, i agree there.
About the common sense, why should the values differ? What does make you think so? I mean, somewhat, sure, but it does seem like a normal world with laws and so on? I doubt that the values differ too much from our world in the middle ages and there we had laws too, it sure was easier to kill someone for something like that, but it still wasnt a normal thought to just kill people that annoy you in some way.
So no, even in that world in that situation giving one chance makes sense, i mean, the killing intent was obvious, he made clear that he would kill him if something like that happens again. (I do agree that this would change if the guy would have tried to really kill abel, but as i say, while it seems so in the manga, i doubt that was the intention, because it just wouldnt make any sense in the flow of the story. Havnt read the LN, but probably would take a bet that the scene is differently written there and not as a "this hit would 100% kill him")