The way they join you and their personalities/conversations, I don't really find them compelling. I guess the personality and conversation part is subjective, but at least the direct way they join you kills the suspension of disbelief.
I mean, a magic-hating merc who doesn't trust anyone suddenly pledges her life in two complete strangers who claim to be hunters? Not even a little bit of holding back? Straight up join and kill whatever they want? Really implausible if you ask me.