Avengers Infinity War is going to be the biggest and the grandest event-movie that has ever been made with the highest number of A-List characters appearing together in one single movie for the first time. It will bring in the prime villain in the entire MCU and it will be nothing like we have ever seen before. Now, what will top this large-scale event you ask? The answer is the sequel, i.e. Avengers 4. Avengers 4 is going to feature even more characters than Avengers: Infinity War and it is going to bring in some insane theories and story arcs that you would not have even imagined to see on the big screen within the MCU.
Now the new set photos that have hit the internet, hint a major event occurring in Avengers 4. In these set photos, we get to see Tony Stark wearing the same T-shirt which he was wearing during the events of the first Avengers movie. We also see Thor and Loki dressed up in the same way that they were in the first Avengers movie and Thor also has the same long hair. Now it is highly plausible that these are just for mere flashbacks, but there are various theories that suggest our favorite heroes will, in fact, be going back in time right back to the events of the first Avengers, which will be the first time we are going to witness Time Travel in the MCU.
First of all, what we see with Tony is that he has the same cut and bruise above his right eyebrow which he did during the battle of New York and we saw it when he was trying to contact pepper while carrying the Nuke out of the city into the portal. So, this could not just be a mere flash-back, it has to be some big event that needs to be altered in order to prevent a dark future. So the Avengers are going to go all the way back in time to the point when the battle of New York was taking place or somewhere close to it.
Also, we see set photos of Thor and Loki where Loki has his face covered and they both are dressed the same way they were at the end of the Avengers when Thor was taking Loki back to Asgard along with the Tesseract and Loki had his face covered.
Now what big change that has to be made is yet unclear but my theory is that they could somehow switch the cube and later on, Thanos gets a fake Tesseract and is not able to finish his Infinity Gauntlet.
Time Travel could happen in two ways and the Avengers could use either one of those. The first is that Doctor Strange becomes very powerful and has mastered the sorcery of opening time portals to exact moments of time allowing others to pass through those portals, which he does regularly in the comics and we have already seen him manipulate time in the first Doctor Strange movie where he actually reversed time and caught Dormammu in his time-loop. The second way of Time Travel would be by using the Infinity Gauntlet and the Time Gem in order to go back in time.
Now, these scenes could always just be mere flashbacks but as we know, with Marvel, everything is big and insane and as we have already seen time-manipulations in Doctor Strange, we know that time travel is, in fact, possible, so this would surely be a time travel event for sure.
Avengers 4 will be the end of phase 3 and next phase would probably include The Inhumans, Black Panther sequel, Captain Marvel sequel, Dr. Strange sequel, Guardians of the galaxy 3 etc. One thing which is absolutely clear looking at the roster of superhero movies in the pipeline is that we will see a huge influx of mysticism and magic in Marvel movies in phase 4. The big villains could be Dormammu, Mephisto who are powerful cosmic villains who can fill the void post-Thanos extinction. Well, at this point, we can only speculate.
Avengers: Infinity War to arrive in theaters on May 4, 2018, Avengers 4 is likely to come a year later on May 3, 2019. CHEERS!