When Does "Demon Knights" #0 (2012) Take Place?
"Demon Knights" #0 "The Prologue" is a historical fiction fantasy comic-book written by Paul Cornell that released September 12th, 2012. So when is "Demon Knights" #0 set?
It takes place on the fictional DC Comics Universe timeline in the year:
We know this because "Demon Knights" issue #1 includes a "Prologue" that begins with free-floating text reading "Four centuries ago. The last night of Camelot." and the rest of that issue takes place in 1013 AD. (Camelot is the quasi-historical British capital under the legendary British King Arthur, who may or may not have lived in the real world at all.) Conceivably, this loosely puts "The last night of Camelot." roughly at 613 AD and this entire issue takes place in this setting.
1,013 - 400 = 613.

613 AD
We know this because "Demon Knights" issue #1 includes a "Prologue" that begins with free-floating text reading "Four centuries ago. The last night of Camelot." and the rest of that issue takes place in 1013 AD. (Camelot is the quasi-historical British capital under the legendary British King Arthur, who may or may not have lived in the real world at all.) Conceivably, this loosely puts "The last night of Camelot." roughly at 613 AD and this entire issue takes place in this setting.
(When "Demon Knights" #0 was made the entire DC Universe had shifted from the universe as published up until late 2011 but in an alternative take in "Madame Xanadu" #3 (2008), which certainly takes place in 1274 AD, Nimue Inwudu/Madame Xanadu expresses in an internal narration textbox that "It has been nearly four hundred years since I last stood in his presence." referring to the Phantom Stranger, whom she last saw during "the down-fall of Camelot!" That math would put us somewhere between 875 AD and 924 AD for this story.
1,274 - 350 = 924
to
1,274 - 399 = 875.)
It is a chronologically early comic in the DC Comics Universe multiverse timeline (a first chronological story to feature Jason Blood/Etrigan The Demon and Nimue Inwudu/Madame Xanadu) and can be read at its timeline point or as an extended flashback.

