User blog comment:Teal of Team TEAL/How does the Grimm make new members?/@comment-4830106-20130916163449

"smoke" theory: The majority of Grimm monsters are comprised of a substance called "smoke" (lower case) in the same way that humans are comprised of "dust". The leading hierarchy of Grim (humanoids) are composed of "ash". Basically, Grim monsters are not animals, so much as artificial constructs that are given animation by the Grim hierarchs. That, or they're animals that have been killed and reanimated in some unworldly form by the hierarchs, through use of "Smoke" (upper case). "Smoke" is the Grimm equivalent of "Dust" (the weapon kind) and can be used to power inanimate constructs. Example: The giant armor.

This theory is largely made up by me, although I have seen it in similar forms. "Smoke theory" just has a nice ring to it.