With the exception of him popping up in The Flash Season 6 episode “Marathon” to help Barry Allen come to terms with Oliver Queen’s death, we haven’t seen David Ramsey’s John Diggle since Arrow concluded in early 2020.
However, the character will soon make a big comeback, with Diggle appearing on episodes of nearly all of the currently-airing Arrowverse shows.
As far as his Batwoman appearance is concerned, it turns out that Diggle will play a key role in the journey of one of the show’s main characters: Luke Fox.