The back-up material at the end of each issue of Doomsday Clock contains more than just world-building Easter eggs.
Like the original Watchmen comic book series by Alan Moore and Dave Gibbons, every issue of the crossover Doomsday Clock contains in-universe supplemental material. These world-building extras include everything from news stories to case files to hand-written notes about different facets of the DC Universe, including the series' central mystery surrounding the Superman Theory. Writer Geoff Johns confirms that backmatter actually teases future developments.
"The story is set slightly future in the DC Universe from now. The reality is some people read the issue and they don’t go into the back, and I hope they read the backmatter," he told Newsweek. "It’s more grounded and inward and for DC fans, if they look closely they will find new ideas and characters that they are going to see come to light."
This lines up with previous comments from Johns revealing that Doomsday Clock takes place approximately one year into the future of the current DCU. Johns noted that DC's current publishing schedule will catch up to the events of Doomsday Clock by the time the final issue of the series is released next year. Supporting this, eagle-eyed readers have noticed that much of the back-up material running at the end of every issue of the series is actually dated one year ahead.
With Doomsday Clock nearing its halfway point, it will be interesting to see what the state of the DC Universe is in a year's time.
Written by Geoff Johns and illustrated by Gary Frank and Brad Anderson, Doomsday Clock #6 arrives July 18 from DC.