**SPOILER WARNING! Here's a quick run-down but fair warning – spoilers ahead!**
The swan song followed Arrow's survivors in the aftermath of the five-part Crisis on Infinite Earths crossover event, which ended two weeks ago with a special Legends of Tomorrow. In that episode, Stephen Amell's late, great Oliver Queen sacrificed himself in order to reboot the universe and create the combined Earth Prime universe that all the Arrowverse heroes now inhabit.
Tonight's finale mostly focused on the supporting players as they attended Oliver's funeral while also showing flashbacks of the Emerald Archer and sweet moments from the past that weren't in earlier episodes. Among those was a scene that shed light on Ollie and John Diggle's (David Ramsey) friendship. There's also a touching moment when his present-day wife, Felicity Smoak (Emily Bett Rickards), meets her adult daughter from the future, Mia, and is later reunited with her husband in the afterlife after she's brought there by Monitor and the two share a long-awaited kiss.
But where things really get interesting is in Arrow's final moments. Diggle, of course, is the Green Arrow's bodyguard, a former solider who goes by the code name Spartan. In the episode's close, as Diggle teases adventures to come, we see a meteor streak across the sky and hear Diggle's voice saying "expect the unexpected." He then goes to the crash site and finds a box with a glowing green meteor to set up the stunning revelation: John Diggle may well become a member of the Green Lantern Corps.
"If the past eight years has shown us anything, it's that this universe is far bigger than any of could dare imagine," he says in a voiceover.
As Arrow fans are well aware, it's been a long-running theory for years that Diggle would turn out to be the famed Green Lantern John Stewart. We learned his grandfather's last name was "Stewart" a while back, and an alternate universe version of the Flash once asked Dig "where's your ring?" when he met him. So yeah, they've been dropping those Easter eggs pretty hard for years.
Ramsey noted recently that the team's “been talking about that ring since Season 1.”
Whether Diggle's Green Lantern is the one we'll see on Greg Berlanti's upcoming HBO Max show is still TBD, but it wouldn't be unexpected.
Here's some brief Twitter reactions to the Green Lantern news:
Diggle has more than earned his stripes as a hero, and it's great to know he has some intergalactic adventures waiting down the line.