In the series Arrow David Ramsey played John Diggle/Spartan throughout all eight seasons, as well as made guest appearances on Supergirl, The Flash, and Legends of Tomorrow, and according to Deadline, Ramsey is slated to return to The CW's Arrowverse for guest appearances that will be spread across multiple shows.
Ramsey will be reprising his role of John Diggle in upcoming episodes of Superman & Lois, Supergirl, The Flash, and Batwoman, and will also be playing a "mystery role" in Legends of Tomorrow that is currently "being kept under wraps." The last time we saw Diggle was in the series finale of Arrow in which he witnessed the crash of an object from outer-space and discovered a mysterious box containing something emitting a green glow. It's been assumed that the contents of the box was a power-ring and that Diggle will become the new Green Lantern, so perhaps that's something we'll see play out across the five episodes. In addition to appearing in five episodes across the Arrowverse, David Ramsey will also be directing five episodes, having previously helmed two episodes of Arrow. In a statement, David Ramsey said:
I remain in awe of the imprint these shows have had on television and I’ve been blessed for the better part of a decade to be a part of them both in front of and behind the camera. To say I’m excited beyond belief to return to the Berlantiverse would be an understatement. I can’t wait to continue telling these stories.
As far as the future of The CW's Arrowverse goes, Arrow concluded earlier this year with its eighth and final season, but there's still plenty of Arrowverse to go around as the second season of Batwoman will debut on January 17, 2021, the fourth and final season of Black Lightning will debut on February 8, 2021, the seventh season of The Flash and the first season of Superman & Lois will debut on February 23, 2021, and the sixth season of Legends of Tomorrow and the sixth and final season of Supergirl will launch mid-2021.