By the late 20th century, it had become near-impossible to continue living in secret, both because of the proliferation of humanity and its technology and temperament.
Scattered worldwide, with differing ideas and motivations, the Shadow Dwellers included, among the most public, Doctor Zero, Powerline, and the Order of St. George.
The Shadowline Saga stories were set in a shared universe within the Marvel Comics Multiverse which was retroactively designated Earth-88194.
Doctor Zero, Power Line, and St. George #9 - 13 were supposed to be part of The Shadowline Saga "Critical Mass" crossover.
Alternate reality versions of Doctor Zero and St. George appear in the first issue of Squadron Sinister as a part of the Marvel Secret Wars event.