More than three years after it launched, another Easter egg has been discovered in Batman: Arkham City, and it's another cryptic conversation with Calendar Man, one that seems to portend the end of the series.

Rewind: In Batman: Arkham City, visiting Calendar Man in his cell on a particular day — St. Patrick's Day, or Thanksgiving — would trigger a conversation regarding some hideous holiday-themed crime he committed. Players could either wait until the day arrived on the calendar or, if they were impatient, set their system clocks forward (or back) to hear the conversation.

Well, the latest talk requires a player to set the system's clock back nearly 10 years, to Dec. 13, 2004. Visiting C.M. on that day reveals the dialogue. (Skip to 1:54 of the above video to hear the talk.) The YouTube Account Batman Arkham Videos puts it all in context: Rocksteady Studios, the series' developer, was founded in December 2004, and Calendar Man's cryptic ramblings seem to allude to the studio's early years. They also run down how this Easter egg was uncovered, which appears to have come at the prompting of Rocksteady itself.

"Do you remember my early work? Flawed, but it showed promise." Calendar Man says. "The end of days is coming. I was there at your beginning, and I will be there at your end." It seems to indicate the conclusion of this series is at hand. Batman: Arkham Knight, of course, is coming in June.