i doubt the other 8 youma are going to be used in the manga b/c then it would become a mythological anime.

maybe one or two more would be ok, maybe in another ninja.

thata would be a cool enemy.

no gaara's demon is a sand preist reincarnated into a badger. (go figure)

does anyboyd know the other youma like what are they and what animal do they represent?

i doubt the akatsuki want the other demons but just kyubi , like y for other when u can get the strongesdt which can defeat all other 8 that would be awesome.