8. The Split
The cause of all the falling out is suspected to be a new set of laws brought forward after the destruction that the Avengers caused in their pursuit of Ultron (or perhaps another, similarly destructive event), essentially turning all superheroes into glorified cops who answer to the state rather than their own conscious. On side with the idea is Tony Stark, who looks set to lead a team of government registered heroes who will more than likely be tasked with bringing in Captain America and his anti-registration team. What we know for certain is that Steve Rogers and Tony Stark are going to have the mother of all arguments over the so-called Accords. Its unlikely that the two will come to blows right away, but Captain Americas moral differences with Iron Man have boiled up nicely over the course of Phase 2 and the moment that they finally throw down the gauntlet to one another should be more than tense enough without the physical element - that awkward moment when you dont know which superhero to side with.