The comic was originally going to be canon, but James Tynion IV, who took over the writing duties on Batman (Volume 3) from Tom King, said that Batman/Catwoman was moving away from the “bounds of continuity” per his understanding and it would have no effect on the main Batman title.
King later stated it was a standalone series and was his version of how Batman and Catwoman’s ending should be. He also hoped it would lead to “breaking the mold” in DC about Batman’s status quo. The series follows the duo’s romance through multiple eras, unlike the current Prime Earth continuity.
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