We can blame Harry Potter and the Deathly Hallows for beginning the terrible trend of breaking franchise finales into two parts, the better to wring every last penny from a willing audience. We've been fortunate that Marvel hasn't taken part in this trend yet, perhaps because their films aren't adaptations in the same way Divergent, Twilight, and The Hunger Games are, but if the latest rumor is true The Avengers 3 could be a two-parter. >sigh<
The story comes from The Daily Marvelite, who have a source saying The Avengers 3 will be split into two chapters because the final battle with Thanos is just that big!! Actually, there is a little more to it than that, and it begins with Marvel's announcement of a number of release dates a few months ago. One of those was for May 3rd 2019, a solid pick for The Avengers 3 except that Kevin Feige said we'd see it a year earlier. Lo and behold, a May 4th 2018 release date was added just a week later. The speculation now is Marvel will use those two dates to tell this one massive story across two movies.
However there's more to consider here, and it stretches back to these comments by Vin Diesel last year...
Diesel: I get the call, I go down to Marvel. A great meeting. It was even talking about something so big I can’t even talk about because it’s like the merging of brands in a way, which I won’t get into. That was something way, way, way, way, way down the road."
What Diesel said has kind of been glossed over since he was spreading rumors like a champ for awhile there, but it could have significance now. What's being considered is whether The Avengers 3 would be a two-part movie with the team battling Thanos across both, or if they'll take on one film while the popular Guardians of the Galaxy would take over in the second. So was Diesel telling the truth and this is what he was hinting at? It's an awesome idea combining Marvel's two biggest super teams for one epic story, but can you think of a more appropriate way to tie a bow on Phase Three?
