It is of utmost importance to have a plot that threads through the shows for a while without expressly shouting "there's a crossover coming". If an entire season of a show is obviously building up to a crossover, viewers aren't going to be as much anticipating the final crossover as they will feel constantly trolled and forced to watch other shows for an inordinate amount of time. All highly serialized adventures and soap operas have season long plots and mysteries: there could be a recurring theme or mystery in each show, like a particular string of thefts, murders, disappearances, and happenstances that seem to be leading to the main plot of the season but that are actually feeding a massively well-planned crossover. Ra's Al Ghul's modus operandi is generally the terrorist interpretation of Green Peace by using his notorious killers the League of Assassins. The seeds of his operation's formation - as well as clues that would provide insights and Easter Eggs - could be laid in Gotham while the questions that those clues answer could be wrought throughout the other three shows. The League of course also already exists in Arrow. Vandal Savage is more about dominating his fellow man, which leaves open the opportunity for anything from world domination to political intrigue, to industrialism, and beyond.
Brandon grew from the awkwardness of his youth into the awkwardness of his adulthood. He is the author of the Eat Your Serial Press title "Ten Years Gone: Pomp and Circumstance" and is a contributor on Maglomaniac, Polite on Society, and What Culture.
