Mike is indeed human !! He even farts and all that stuff
Darren however, well, i'm afraid your dealing with a cyber based life form that occasionally leaves the matrix and visits the mechanical wasteland of our mortal world. Those who have crossed paths with this mythical creature speak of streetlamps that dim as he walks by, knives sharpen and forks bend in his presence ( or is that Urigeller ) and if one looks close, you can just make out the corners of all those workshop manuals he's swallowed