Elseworlds is taking The Flash, Arrow, and Supergirl to exciting new places with exciting new faces from DC comics, but some of the new characters are a little less recognizable. Night one of the annual crossover saw Amazo terrorize Central City, but it also introduced John Deegan, based on DC comics character Doctor Destiny. And while his role may seem small for now, he could play a larger part in the story as Elseworlds presses on.
On The Flash, John Deegan is a professor advocating for eugenics to turn humans into metahumans. He's played by Jeremy Davies with the same kind of zeal as his similarly neurotic Lost character, Daniel Faraday. In the comics, there is a character named John Dee who becomes Doctor Destiny. That's most likely who Deegan is based on in the Arrowverse, though that has yet to be confirmed. According to Encyclopedia Brittanica, there was actually an English mathematician and occultist in the 16th century named John Dee, too, who possibly inspired the character of Prospero in Shakespeare's The Tempest. All of them (Deegan, DC Dee, IRL Dee, and even Prospero) mix science and magic in dangerous ways.
In DC comics, Doctor Destiny is a criminal scientist, not a professor, who antagonizes the Justice League using a variety of methods that include an anti-gravity device and a big ol' ruby called the Dreamstone that he uses to manipulate reality. It may be that The Monitor's book, which he gives Deegan in Elseworlds, is taking the place of the Dreamstone from the comics. They serve a similar purpose. Destiny also likes to trap characters in their worst nightmares, which always makes for fun story fodder with ensemble casts. (Buffy and recently Chilling Adventures of Sabrina have both had episodes using this concept.) That could be where this crossover is headed, especially as the body swap has already forced the Flash and Arrow to confront some of their fears... like hugging, in Oliver Queen's case.
Is Deegan in Gotham City? That's what Oliver seemed to determine at the end of Elseworlds' first episode. In the comics, Doctor Destiny was imprisoned in Gotham's Arkham Asylum for a spell. He broke out, like pretty much every criminal villain ever checked into that facility. If Deegan is in fact Dee, then the CW is changing his origin story. When Deadline announced Davies' casting, they said that the nefarious Deegan was an Arkham staff member. IGN points out that the character design of Deegan, if Dee, resembles Neil Gaiman's Sandman comics for DC. Could the professor be moonlighting at the prison?
While both characters have a comic book history, The Monitor and Doctor Destiny aren't exactly pals or allies in the source material, so it will be interesting to see where Elseworlds is heading with these characters. Of course, the truth about John Deegan and who he may or may not become has yet to be revealed — the Arrowverse could go in an entirely different direction. Now that the group is headed to Gotham, they should get more answers.