Sometimes a human can be cursed into being a morph for vicious crimes against humanity, nature, or even themselves. This is rare and is usually not induced by any witch or magician, but by nature itself. Morphs can shift at any time, unless they are cursed. Then the shift depends on the conditions of the curse. Some curses have the morph shifting only when he or she is happy, sad, angry, and so forth.
Some curses also work by the cycle of the full moon.
For the most part Morphs can meet their demise just like any human. Purebloods and some cursed morphs can only be killed in certain ways. Purebloods can only be killed by another Pureblood. No one really knows why this is so. Some theorise that Purebloods are protected by magick because their connection to magick is so intense.