Spoilers ahead for the Arrow season finale.
In a scene near the back-half of Tuesday's Arrow series finale, John Diggle (played by David Ramsey) has a moment that fans have been hoping and pining for since the series began. He got the ring.
Diggle is shown mourning the death of his friend Oliver Queen (as it happened in the "Crisis on Infinite Earths" crossover), but is knocked back by the impact of a mysterious asteroid-like object crashing to the ground near him. It's no asteroid though - inside the crater it left is a box... and in side it, a Green Lantern ring.
“That was something that we’ve been working our way towards for a good long time now," showrunner Marc Guggenheim told Deadline. "I think for maybe about a year, year-and-a-half we’ve known that this was a moment we’re going to be able to do, and it made sense to do it in the finale because my attitude is that even though the show ends, as long as the characters are alive the characters continue on. One of the things we wanted to do with the finale was give you a sense as to what their post-show trajectories would be. And certainly, Diggle’s is probably the most intriguing."
Diggle has twice been teased to be a Green Lantern in the Arrowverse. In an "Elseworlds" episode, it's revealed that his alternate reality self is a Green Lantern. Later on during a Diggle-centric episode, his step-father is introduced, and named Roy Stewart. So that would make John Diggle, if things would have been slightly different, John Stewart. Stewart is, of course, the name of arguably the second-most-popular Green Lantern in the DC mythos.
When asked if this new chapter in Diggle's life would be addressd somewhere in a future Arrowverse series, Guggenheim was cagey.
"That I can’t really speak to because this moment was, like a lot of things, a sort of negotiation with the powers that be about, ‘Okay, what exactly can we show? How far can we take this?’" Guggenheim said. "I think it’s probably best. To me, the bets approach was to let the moment speak for itself and we’ll sort of see where the future takes us."