For the record, since they introduced the element of the multiverse, we don't actually know whether "Constantine" was set on Earth-1 or not. All we know is that Earth-1 also has a John Constantine "master of the dark arts" who may or may not be the one from the show "Constantine". Which they might want to choose to do if they ever do The Spectre, which "Constantine" didn't quite handle that good. Speaking of "Constantine", wasn't the reason some CW executive gave for not picking up that show for a second season that they didn't want to be the comic show network?! Whoever that executive was must feel pretty stupid now. On that note, maybe The CW should try and get "Constantine" going again. It would benefit from the connection to the other shows, but it'd be different enough to also get other demographics who are not interested in superhero shows.