One of the major unavoidable difficulties in making movies based on comic books is that, in cases of mainstream characters, the book is a part of a larger saga. To ask a comic book fan about a particular character will almost always require additional characters to be explained. In terms of other forms of literature that have been brought to the big screen, it is rare for a character in the story to exist in great detail in a separate story. Because of this issue and the need to keep the audience focused on the important facts for one particular film, cameos by other established heroes are rare. When these other heroes do show up, it is typically in a somewhat diminished capacity as this article will sometimes point out. A primary example of this pseudo cameo is a character that didnt make our list, Doctor Leonard Sampson played by the pretty awesome Ty Burrell (Modern Family). However, only serious fans even recognized Doc Sampson in the film, mostly due to Burrell not having flowing green hair, huge muscles, and the worst super hero costume ever. Its weird tip of the cap to fans, which typically and ironically doesnt actually go over well with said fans. But here and there we find appearances of some Marvel mainstays that if done right could helm a movie in their own right.
Disclaimer: The term side character had to include characters that simply werent the star of the film and are not rumored to be given such future star treatment (Fear not, Hawkeye and Black Widow are not on the list)
7. The Warriors Three
Thor was my least favorite of all the Phase 1 films, in fact its simply a terrible film in a lot of ways and Im not surprised Kenneth Branaugh wont be back to sully his reputation as a filmmaker any further. I can say that I liked the Warriors Three enough, and I think they and Lady Sif could be used to right a lot of things wrong with the Thor franchise of underwhelmingness. Where was Baldur? He seems a tad important to simply omit from the story. The Warriors three and Sif should represent the Tales of Asgard back up issues that appeared in the Thor comics for decades. They were typically only a few pages long, but they were an awesome idea. The spirit of the back up stories could be used to create a compelling film featuring Thors compatriots. Using Loki as a catalyst for the story, and an all new villain, the Warriors could set out on an adventure when they all share a dream about a friend named Baldur, a friend they cant remember. In fact no one seems to be familiar with such a God, but the warriors are beginning to remember. As they investigate they begin to discover clues that this person did in fact exist, with the help of Hiemdall the heroes are lead to the culprit and the reason Baldur has been erased from existence, The Enchantress!