"I don't have an exact species in mind. This is just long years of experience with demons as a whole speaking. I might bet on your wards against a common Fyarl or even a master vampire, but not against a hell-god. And there are any number of species who can, for example, eat magic, or subvert any power or force that is turned against them except under very narrow circumstances. Or move through any surface in which their image is reflected. Or command the mind and soul of any who hear their true name."