Greg Berlanti, the creator of the popular Green Lantern film and how that ended up paving the way for the multiple television series that now make up the Arrowverse. Berlanti had a long history in television, having written for series like Dawson Creek and Everwood, before he was hired in 2007 to write and direct Green Lantern for Warner Bros. By February 2009, Berlanti was no longer attached to direct and later confirmed he had nothing to do with the finished product, despite his name being attached as a screenwriter.
In 2012, Berlanti signed on for another emerald DC hero, Green Arrow, and developed what would become The CW series Arrow. Arrow's success led to a number of other DC superhero shows like The Flash, Supergirl, Legends of Tomorrow, and Superman & Lois all set within a shared universe called the Arrowverse, which Berlanti helped develop. He also is an executive producer on other DC series like Batwoman and Black Lightning (which are in the Arrowverese) and Doom Patrol. Berlanti is even involved with the unknown DC project that Jensen Ackles is developing, which is not bad for someone whose name was attached to one of the more widely disliked DC film adaptations.
In an interview with THR, Berlanti discussed Green Lantern's failures and said it was that project that led to the creation of the Arrowverse. Berlanti said it was a heartbreaking experience but it was that time working on Green Lantern that introduced him to people involved with DC television which eventually led to the creation of Arrow. He commented on how things have finally come full circle now that he is working on Green Lantern again, this time as a television series for HBO Max. Berlanti said:
"We’re actually working on a Green Lantern series for HBO Max, so it’s come full circle. The movie did introduce me more to the folks at DC, which led to Arrow. So while it was heartbreaking on the film side, it ultimately led to wonderful things on the television side."
Despite the disappointment of Green Lantern, Berlanti has found ways to sneak references to the film into the Arrowverse. Ferris Airspace has been referenced numerous times, and on The Flash Barry Allen mentioned a pilot that went missing, likely a reference to Hal Jordan. Then, in the Arrowverse crossover event Crisis on Infinite Earths, footage from Green Lantern was shown, designating it as Earth-12 in the DC Multiverse. The finale of Arrow ended with a tease that John Diggle (David Ramsey) would become the Arrowverse incarnation of the Green Lantern John Stewart, but those plans may have been sidelined due to the previously mentioned Green Lantern series for HBO Max.
The Arrowverse has now been running for ten years, and even with series like Arrow, Black Lightning, and Supergirl ending their run, the franchise is still going strong. Both The Flash and Superman & Lois are expected to return for another season, and while Legends of Tomorrow and Batwoman's statuses are still up in the air, two new series are coming to The CW: Gotham Knights and a John Diggle-centric series titled Justice U. On the non-Arrowverse side of things, HBO Max is greenlighting more television series based on DC heroes. The reach of the DC Universe is far greater than when Berlanti was working on the Green Lantern movie, and the Arrowverse is a big part of that.
Source: THR