The difference between the general Mechanist Class and the Bioforger Class Specialization of the Gene Augur Class in terms of their drones is that unlike the drones of a Mechanist, apart from their living characteristics, the nature of a Bioforger's Bio-bots are almost always rigid.
For example, Leon first got the C-5 drone blueprint as a basic drone blueprint but with his own ingenuity and after seeing the technological utility of a NetRunner's powers, he used it in his own design.
With it, he made the C-5 drone capable of invisibility.
For a Bioforger, adding such a trait to their drones is not easy. It would require years of growth and evolution from that specific drone, fed and groomed in a certain way to develop such traits.
This is exactly why Lt. Colonel Umar Farouq brought a few of Leon's invisible C-5 drones with him when he infiltrated the inner ring of Neo Solace.
He couldn't do it himself.
And with them…
Drone Control Matrix!
BZZZ!
