The CW’s DC TV show universe – also referred to as the Arrowverse and/or Flarrowverse for Arrow and The Flash – has expanded a good deal, over the course of the past year.
Now that Supergirl has set up camp at The CW for its second season, crossovers between all-four CW DC TV series are actively being planned too.
Not only did an Arrow/Flash spinoff in the form of DC’s Legends of Tomorrow debut, but a crossover between The Flash and former CBS TV show Supergirl established the latter as being part of The CW/DC “multi-verse.”
However, lest we forget, the most recent season of Arrow (season 4) also introduced Matt Ryan’s John Constantine to the Arrowverse, following the cancellation of the Ryan-headlined Constantine TV show on NBC.