I read somewhere that the hand seals used to perform jutsu are simply a motion component that replaces the verbal component traditionally used in spell casting. This came from an interview done with the creator of naruto. So, if that's the case, then jutsu is magic and I'm wondering if genjutsu (even if it litterally means illusion) is more than just illusion, like charm spells (which is what I think Itachi used). The total darkness technique also seemed like it was more than illusion, just not quite a direct damage or defense attack. Same with zabuza's mist. What do you think?