The fact that Marvel Studios' Marvel Cinematic Universe, Sony's Amazing Spider-Man franchise and Fox's X-Men franchise all take place in different movie continuities is an ongoing and relentless talking point, and the idea of the three - or any combination of the three - merging in the future is a mouth-watering prospect for any comic book or comic book movie fan. Thanks to these studio issues, however, we're all aware of the fact that key characters like Spider-Man himself, the X-Men and their foes and the Fantastic Four can't appear in the Marvel Cinematic Universe alongside the Avengers et al at present. Of course, there are still countless directions that each franchise can go in, thanks to the fact that they all have hundreds (if not thousands) of characters that they can call upon regardless of the characters from the other movie franchises being unavailable to them. That said, this lack of availability of certain characters to Marvel Studios does pose some problems and ensures there are some limitations that each franchise will have to deal with going forward. Some of the best relationships, rivalries, moments and indeed stories in comic book history simply aren't possible thanks to the necessary characters to create them on screen being tied up elsewhere. In this article, we'll be taking a look at a number of the less obvious characters that Marvel Studios can't currently call upon in their Marvel Cinematic Universe and problems that this potentially poses. So with that in mind, here are ten characters it's a shame Marvel Studios can't currently use (and why)... Note there may be spoilers for ongoing comic book movie franchises in this article.