I'm all for pragmatic characters but this dude is becoming straight-up evil, if killing Charlotte would get him closer to finding his sister he would do it.
@kursedkaiju I have to be honest, if he did that at some point, it would be awesome. I can't remember ever seeing such a character in manga before, much less as a main character. It would be amazing to see him struggle with the decision, but to ultimately go through with it? I would honestly be impressed if the author went through with that. I want to see him make morally wrong decision for the sake of furthering his goal, just because it would be so unique.