5. Kang The Conquerer
Marvel ComicsIn the absence of Doctor Doom from the Marvel Cinematic Universe, the next best tech-genius bad guy is undoubtedly Kang the Conqueror - and with a potentially great version of Doom coming to our screens in the Fantastic Four reboot movie, Marvel Studios could do a lot worse than bringing in a villain with similar traits to the legendary Avengers foe. Age of Ultron could be the ideal time to formally reference Kang's existence in the Marvel Cinematic Universe. In the comic books, in various realities including the main 616 universe, Kang the Conqueror and Ultron have crossed paths - for example, Kang has attempted to enlist the assistance of the Avengers to defeat his robotic enemy and Ultron has manipulated Kang into attacking the Avengers - and Ultron's very existence in the Marvel Cinematic Universe is a good enough reason for Kang to make his presence felt. Given that Kang is all about technology, the technology used by and used to create Ultron could prompt the genius to want to learn more about him. He could base his armour on that of Ultron's shell and then use his genius to improve it to accommodate the gadgets we know Kang possesses in the comics. Essentially, there's a Doctor Doom-shaped hole in the Marvel Cinematic Universe which is as big as a hole in the DC Cinematic Universe would be without Lex Luthor or the Joker. Kang could fill that hole and Age of Ultron could be a good way to introduce him - even if it's just in a short scene during or after the credits.