The reveal of Thanos at the end of The Avengers was the next big promise of much grander things to come, second only to Iron Man's post-credits sting in terms of excitment. Two and a half years later, Phase 2 is almost over and we have had just a couple of scenes with the master villain in Guardians Of The Galaxy. Thanos is part of the long game for the Marvel Cinematic Universe, although we won't see his full potential for a few more years yet. Given that his story is taking centre stage at the latter half of Phase 3 - the 18th and 20th films to be exact - introducing him at the end of film six was a great piece of foreshadowing. What it has done is establish the idea of who the big bad really is, slowly setting the pieces of the puzzle in place. As such, he hangs over every story as a bigger threat to the events that unfold. Thanos could have been revealed for the first time after Avengers: Age Of Ultron or even Guardians Of The Galaxy 2, but it speaks to the forward planning of the Marvel Cinematic Universe that he has already been in play for so long.