The Exo-toas were used to defeat the Bahrag, but they never said that they were good. They were mechanical suits, and they could have been used to some day controll the toa without krana and they would be locked in a super suit that would destroy all of Mata Nui itself. They said that they could be used without a piolot, right, so, whn they were exposed to the protedermis, they could have changed to nuva, and turned evil and after all they were made by the Bahrag, maybe, and that would be a reasonable explanation as to why they made them, and they discovered them to soon, and used them to thier advantage. The little bumps behind them also have the same color eyes and were at the same place that the toa were when the Bahrag were defeated. I think this is a reasonable explanationa, and if you do not agree, then tell me, I'd like to hear about it. Thank you!

um actually after the toa dump the Exo the toa go in individual toobs deep underground were they became nuva the exos bahrag bohrok were no where nere the protodermis chambers

the exos are independent and they have names that i will not reveal to you.

the exo-raptor form or exo-toa form will aid in protection of the koros while the toa are on their mission to stop the new enemy

but, the exos could have been able to walk around, like they said, and some get exposed to the protedermis! They didn't know that the bumps were there anyway, or how they got there, and so, why not it be them???

I was responding to jala21