steampoweredstrawberry:

The wild thing about Bioware’s hatred of blood magic and its practioners is that they unintentionally spent so much time in DA2 hammering in the concept that blood magic itself isn’t inherently evil, and the user’s intent determines whether blood magic will cause more harm than it’s worth.

There’s obviously Merrill, who educated herself on safe blood magic practices and never once used it to cause harm except in combat situations. In fact, she successfully uses blood magic to cure the taint from the Eluvian. She never accidentally summons demons. Nor did she engage in sacrifices.

Alain uses blood magic to free your sibling/lover from a magically induced coma. No demons. No sacrifices. His magic is successful.

Even Gascard, who isn’t the best of people, helps using blood magic by using it to track Hawke’s mother. Again, there are no side effects. Just blood magic helping people out because that was the user’s intent.

We also know that Orsino had been studying blood magic for quite some time with no backfires or demons until he chose to active summon a demon. I don’t regard that as canon, but the point is, he never caused harm until he meant to do so.

TL;DR: Blood magic is only bad if you use it to do bad things and canon supports this.