Exactly what Mata Nui's original mission is gets revealed next year.
The Kanohi Dragon was created by a Makuta. Miserix did not create it.
On the Matoran universe: "You have to keep in mind that the beings who consider it a universe are the ones who live in it. Basically, Mata Nui is giant robot with millions of nanotech beings inside of him and various mechanical "organs." So in that sense, you could even argue he is more like a synthezoid, a living being whose parts are all mechanical. So he has a universe inside him the same way you have one inside of you. You have living bacteria in your body, a waterway (your bloodstream) that travels the length of your body, and various places for the bacteria to live. Something in your liver that wants to travel to your brain would sail on your bloodstream, the same way someone who wanted to get to Metru Nui would sail on liquid protodermis to do it."
Greg: "The bone hunters and the Skrall were already in an alliance at the time of ROV. But Tuma wanted to a) make sure the bone hunters were strong enough to be worthy of being allies and b)see them bloodied enough by the Glatorian so they wouldn't be TOO strong a threat to turn on the Skrall."
The Element Lords are considered mutant versions of their original Glatorian species.
The Element Lord of Sand does not have a stinger tail, since the Vorox had not yet been modified by the Great Beings by the time of his selection.