3. Hinting At Future Villains
One little tool that each franchise has utilised to heighten interest in future movies is hinting at future villains. Thanos was hinted at throughout the Avengers movies (with Loki and the Chitauri referring to a higher power being the mastermind behind their plot to take over the Earth) and then, of course, after the credits he made a very brief appearance by turning to the camera and smiling in a sinister fashion when The Other suggested that attacking Earth again would be very risky. Similarly, at the end of Batman Begins, after James Gordon has been promoted to Lieutenant, he is talking to Batman atop a roof and showing him the Bat-signal when he mentions a criminal who leaves Joker playing cards at crime scenes as his calling card - obviously this would lead to the appearance of the Joker in the sequel, The Dark Knight. In the Iron Man movies, the Ten Rings were mentioned throughout the trilogy until, ultimately, it was revealed that the Mandarin (Aldrich Killian) had appropriated the organisation's name for his own schemes and had also been funding the organisation during an unspecified period prior to the third movie. On an less obvious note, Samuel Sterns showed signs of becoming The Leader in the Incredible Hulk movie when some of Bruce Banner's blood dripped in to his head wound, causing his cranium to deform slightly, although this has yet to be confirmed.