Thaumaturgy tends to be regarded as a "Bad, Very, VERY BAD" in just about everything I've ever read. It's regarded as playing with life and will, either your own or another person's, and thus isn't... um, reliable is a good term. So it comes to bite the user and those around them in the ass in unpleasant ways.

Knowing that the first two were once one book makes me believe we'll get to see Vey at the end of The Virtu. I massively "GRR!!" at UPS, who have failed to deliver my copy of that and Blood and Iron for two days.