Gaze with his youngest daughter, Jessie, and were doing a hunting lesson, but there happened to be hikers in the area. A quick fact about demons, is that they are very, VERY protective and territorial, especially if they happen to have children. Jessie is also still very young, and baby demons (called pups) are blind until they reach 2 years old.

Since Jessie is just barely 1, she doesn't know what's happening. What is happening, is that one of the hikers got a tad too curious, and close, for dad to be okay with. Of course, he's overreacting, but unless you want to be mauled by a pissed off parent with dagger teeth, stay a good ways back. And the purple stuff coming out of his mouth is a highly corrosive and highly toxic acid.

Upon contact, it will immediately eat away flesh and bone in minutes. All the more reason to back the fuck up. Or at least ask to get closer.