There have been multiple rumors and teases of an Iron Man 4. Robert Downey Jr went on the Ellen Show and confirmed it! Then, the next day, he shut it down... That is the power Ellen has. One day he is talking about it, the next it's not happening. Mel Gibson offers to direct, still not happening.
[Iron Man 4](movie:886190) needs to happen, Iron Man 3 left too many strings (get it) loose. WE NEED TO SEE THE FRICKIN' MANDARIN! WE WANT FING FANG FOOM! WE NEED HIM TO TRAIL OFF TO THE GUARDIANS OF THE GALAXY! It's not too late to be announced and many fans are demanding it. Heck, even Robert Downey Jr wants it to happen.
But, if it were to happen, there is a way. We had been hyped up to believe we will see The Mandarin. Iron Mans greatest nemesis, but we had none of that sort. We got this Shane Black BS about an actor pretending to be a terrorist while the director of AIM is the big villain with weird fire powers called Extremis. There is still yet a way to include the Mandarin and another major Iron Man villain. It would all start with an Ant-Man one-shot....
Xandarian Head of Security, Richard Rider is just a normal space cop. No powers. There he is, just minding his own spacey business when out of knowhere (hehe get it) the Phalanx attack Xandar under orders of Ultron who is under orders of Thanos (it's a long story). Richard rushes in to save the most important objects that the Nova Corps have ever contained. Infinity Stones. He grabs the Power Stone which was contained after Ronans attempted genocide on Xandar and the yet to be revealed Soul Gem.
Richard then tries to escape but putting the two gems too close together causes a reaction. The Soul Gem works with the Power Gem and gives him powers since the Nova Corps officials have none so far. He also has a cybernetic implant on his arm which has full access to all the Nova Corps files. The Soul Gem then combines this implant with his mind so he has every ability Nova has. He then barely escapes to find the Guardians of the Galaxy.
While all the chaos and destruction on Xandar ensues, a prison break releases multiple villains into the MCU. These villains would include Kang the Conqueror (yet to gain powers), Michael Korvac (yet to gain powers), Moondragon, and...... *drumroll* Fing Fang Foom.
Fing Fang Foom then goes off into space in Earth's direction. He arrives only to terrorize Dubai. Tony Stark is not too far off after learning about a real Mandarin from Agent Coulson (who I bet reveals himself to Stark at the end of [The Avengers: Age Of Ultron](movie:293035)). He then gets a distress call from Quicksilver and Vision who are trying to stop Fing Fang Foom. This battle could be done very well and look very, very cool. In the end, the good guys would hand Fing his a** and Fang would run off and shapeshift into a normal human maybe by the alias of Eric Jones as an easter egg but not fully revealing the character.
He finds the Mandarin or should I say, the Mandarin finds him. The Mandarin has been on Iron Man's case since day one. Foom just made a mortal enemy with Tony and plans on destroying him. So Mandarin and Fing team up.
The problem is, Stark is going through a lot of anger and depression. First of all, he has PTSD from the events of the 2012 invasion (The Avengers), the destruction he caused by creating Ultron, the death of a James Rhodes, the lose of Bruce Banner (not dead but on Sakaar) the Civil War that he chose the wrong side on, and the death of Steve Rogers immediately after the events of the war. He has a lot of issues going on. So the suit he is wearing currently is a more Superior look mixed with the concept art of the stealth suit.
Quicksilver and Vision head back to the Avengers Tower on Avengers business while Tony dismisses this deal on his personal business of hunting down the Mandarin. Tony then finds the Mandarin in Eastern China and gets the crap beat out of him. He barely escapes.
The now extremely pissed off Tony Stark goes back to New York and tries to figure out the Mandarins and Fings weaknesses from footage. He finds that the Mandarin is moving to attack an Sydney, Australia and take the country by storm and Fing is of alien origin.He gets intel from Vision that a SHIELD research/defence submarine (which is holding information critical to Coulson and his [Agents of S.H.I.E.L.D.](series:722469)) is under attack by Fing nearby Sydney and that they are unavailable to aid. He heads off to Sydney while Pepper begs to go. He denies her help.
He is now in his diving suit and does an underwater battle with Fing. Fing Fang Foom is killed in the end while Sydney is under a major attack from the Mandarin and his terrorist allies. When he arrives, he is surprised and angry to see Pepper has come in a pink, silver, and white iron suit. Her Rescue armor. He tells her to go back but is soon attacked by the Mandarin. Tony and Pepper do battle with the Mandarin and the his henchmen. In the end, Tony wins but with massive casualties on the civilian side. He is now distraught and tries to tie up ends. He breaks up with Pepper, builds a deep space suit and launches off hoping to find Banner and to take a rest from the world he tries so hard to protect but never stays clean. He is sick of the memories Earth brings him. So he heads off into space and finds Banner and the [Guardians of the Galaxy](movie:424073) who eventually return to Earth to stop Thanos.