[quote=@Lucius Cypher][hider]Now what ever indicated that Penny was a prototype? For all we know she is the result of testing from prototypes, which presumably is what Gren is. As I've mentioned before, while Gren is not primarily robotic he is a cyborg, not an android. He was once a faunas and simply started replacing parts of his body after getting more and more injured. Penny on the otherhand is fully synthetic i.e. was never born conventionally.

The main difference is most notable with the machine that helps Gren work his aura. On it's own, what he uses isn't enough to produce aura, so he feeds it his own so that his aura can be used throughout his body. Conversely, whatever Penny is using is powerful enough to produce it's own aura, instead of being fed by an already existing aura. Not to mention that even if we were to use what you're suggesting, Gren still would be actively pumping aura through his body the same way he would be actively breathing; it's just something he'd always be doing. More so since Gren actually relies on his aura to power his body. The only reason he eats and such is both for the taste and to create biofuel for his thrusters, which isn't necessary for him to function anyways.

Of course, then we'd have to debate what is more effective armor: Aura or one and a half inch thick armored flesh.[/hider][/quote]

What indicates that Penny was a protoype was the fact that she was still in testing phase. She was enrolled at Beacon to test her capacity to pass as human and the part of her AI that controls social interaction. The fact that this needed testing means that the andriod while complete was not finished with the quality control phase of production. That means the likelihood is that she was the only one as building more androids off a schematics you are not entirely sure is viable is just foolish.

Aura is a type of energy but I don't recall anything indicating that it could be used as a power source or that it could be amplified by mechanical means. Penny as far as we are aware was the first foray into synthetic aura production but let's assume for a moment that she wasn't. The technology you are proposing exists in Gren is suppose to be outdated, several years old at least except that same tech would make all of the power systems in RWBY completely and totally obsolete. If you can build machines that are powered by aura and machines that amplify aura there wouldn't be a need for any other form of power supply such as the dustricity that is most common on the show. Aura has no byproducts, it is a completely clean energy source if it could be used in that fashion. The fact that Remnant still operates on other methods means that it can't.