IRON MAN
Real name: Tony Stark
Actor: Robert Downey Jr
Prior film appearances: Iron Man (2008), The Incredible Hulk (2008, mid-credits), Iron Man 2 (2010), The Avengers (2012), Iron Man 3 (2013)
Our favorite billionaire/playboy/philanthropist/superhero's snarky confidence is what ironically endears the audience to his character, but this Avenger is likely more bravado than self-assured. His age-old daddy issues aside, we see Tony battling post-traumatic stress and anxiety, arising from the events after The Avengers, and the fact that he is but a mere, albeit very intelligent human in the face of Gods, Tony's past is littered with physically and mentally taxing problems like alcoholism and a rebellious streak, probably stemming from earlier mentioned paternal troubles.
Secret: Tony is a nervous wreck trying to cope with PTSD
Remember all those suits Tony was making in Iron Man 3, over 20 variations which later took part in the battle against Aldrich Killian and his Extremist soldiers? As quoted by Robert Downey Jr, "I think he realizes that tweaking and making all those suits in the world, which is what he has been doing since the first film, still didn't work for that thing of his, kinda his tour of duty that left him with a little Post-Trauma Stress Disroder (PTSD) (having nearly died towards the end of the first Avengers film). So his focus is more on how we can make it so there's no problem to begin with, that there's a bouncer at our planet's rope." Cue Tony's well-meaning but disastrous invention of ULTRON.
