The responsometers are now described as containing an "artificial soul" invented by Doc Magnus, as inspired by T. O. Morrow, who is revealed to have taught him at college and to have been the only one not to laugh at Magnus's theories. After the unexplained dismantling of the Metal Men, Doc Magnus is unable to recreate these souls and restore their personalities. He now takes Prozac for the bipolar disorder which caused his nervous breakdown and the depression which led to the creation of the Plutonium Man, a tremendous, nearly indestructible superweapon based upon the Metal Men, but with Magnus' then-own deranged, twisted worldview as its operating system. It is implied that although the medication is keeping Magnus from doing anything irrational, it is also deadening his imagination and creativity and that this is the reason he cannot recreate the Metal Men.