Pretty complex this ^^:

So i'd assume they're like a poltergeist? They were once an unanimated thing (like a skeleton, a doll or a rock) that was possessed by something else that brought it to life? And the 3 variations (ashkin, soulkin and forgekin) being based on what they possessed? If it once was a living creature it become ashkin, if it was man-made object it become forgekin and if it was part of nature it become soulkin?