very cool. It looks great though (and it might just be from loading it on the internet) but it seems really dark and hard to read in some areas. It could help to up the contrast between the dark and light areas to make things really pop in this image.
They look like they would belong somewhere so I was just curious. ^_^ A few places I've found that their ancestors might have belonged to is the firey Kiln fiends from Zendikar. Or perhaps the Ragemutts on Ravnica or the hounds that devils ride on Innistrad. All of those are deadly and/or destructive if I remember right.