"Blood magic is magic controlled by bloodletting or sacrifice. It's...not a good thing, at all. Torture is usually involved somewhere along the line, from what I hear. But that's only what I've heard, anyway. I don't go out of my way to learn about magic very much."

She doesn't know much about the magic itself, given that she'd never expressed any magical talent at all, so she never bothered to read up on it. Most of it is gleaned by cultural osmosis, much of which she knows not to trust. But this, she knows to be true, that blood magic is bad news.