The CW began airing Arrow in fall 2012. Due to its success, the network began production for a The Flash spin-off the following year. Barry Allen was planned to be introduced in the eighth and ninth episodes of the show's second season, followed by the twentieth episode acting as a backdoor pilot. However, after executives saw the initial episodes, they decided to order the series straight to pilot. In early 2015, the CW announced a web-series for Vixen to air on the CW Seed.. Two months later, The CW announced an additional series, DC's Legends of Tomorrow to air early 2016. On August 12, 2015, Wendy Mericle confirmed their version of John Constantine follows the same continuity as NBC's Constantine.