In the series finale of Arrow, the show (sort of) made good on years and years of teases and fan-theories with longtime sidekick John Diggle finding a mysterious box with a green glow that had just come crashing down from space, heavily implying—if not outright saying—that Diggle had found a Green Lantern ring. That, at the time, seemed like the last we’d ever see of Diggle, since HBO Max was already making its own Green Lantern show that probably wouldn’t waste its time by also being an Arrow spin-off, but now it sounds like the Arrowverse might have something surprising up its sleeve.
As reported by Deadline, David Ramsey (who played Diggle for all those years on Arrow) will be coming back to direct and guest star in five episodes across the Arrowverse, reprising his role as Diggle in Superman & Lois, Supergirl, The Flash, and Batwoman. When he stops by Legends Of Tomorrow, though, he won’t be playing John Diggle. Instead, he’ll be a “mystery” character whose identity is “being kept under wraps.” Now, Legends fans will know that the show’s next season is going to involve aliens, as in aliens from space, and you know who lives in space? The Green Lanterns! They’re space cops! He probably won’t be John Diggle as a Green Lantern, but he could be the John Stewart Green Lantern from the comics and Legends could easily lampshade it with someone saying “hey, you look like John Diggle” and he could say “well, I don’t know who that is because I’m a different guy.”
Interestingly, the Deadline story doesn’t mention if there’s any reason for John Diggle appearing in all of these episodes and David Ramsey directing all of these episodes. It might just be a weeklong David Ramsey celebration event, or it could be a Diggle-centric crossover series, but we don’t know either way. We also don’t know when any of this is happening, but thankfully Green Lanterns tend to recite a whole little speech when they show up to places, so we should have some advance warning.