On the contrary, there is a certain NPC in the desert who swears that he hears them through the chasm. If you're talking about "blasphemy", then there are a few things that come to mind that "have been allowed to happen" in the story line. Shiva being the first thing. He laying with dragons is a heinous crime, and yet here she is. Another comes to mind, but it would ruin a certain part of the main story, so I will talk in riddles. It involves a certain crystal and a bad guy. That was suppose to be impossible to do, and yet it happened.
There is no such thing as "impossible" in a video game, and every story has those that dare to go against all teachings. Satasha HM anyone? Chalk full of dead... things. I could also come up with a plausible story line that could introduce necromancer in some form or fashion that doesn't destroy the entire balance in Eorzea. All it takes is dedication, some time, and some effort.
