Although comic book movies have grossed billions of dollars worldwide, there was a time when making one seemed like a gamble. With over $17 billion earned across 20 films, the Marvel Cinematic Universe is probably the most successful superhero franchise in history, proving that superheroes work on the big-screen. However, there are a lot of characters that Marvel Studios can't use thanks to past financial troubles. The rights issues surrounding various Marvel characters can get complex, so we've made a video outlining the history of the rights to various Marvel characters.

As it looks like Disney's impending acquisition of key assets from 21st Century Fox will go through, there's a pretty good chance that a number of characters -- including the Fantastic Four and the X-Men -- will be available for use in the MCU. However, there are a number of other characters for whom the future is a lot less certain.

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Check out the video below for a complete guide to the various rights issues surrounding various Marvel characters.

Whether Marvel Studios will ever regain the rights to Spider-Man and his associated characters from Sony Pictures is hard to predict. Considering the massive success that was Venom, it seems unlikely that Sony will part with the rights any time soon. However, there was once a time in which it seemed impossible for a live-action X-Men team to share the screen with any member of the MCU's Avengers, so that might not be a problem that continues forever.

There's also the matter of Bruce Banner/Hulk, who has an incredibly complex rights history. In 2017, actor Mark Ruffalo remarked another solo film focused on his Bruce Banner/Hulk wouldn't happen. As it stands, there's little chance the character will appear outside of another hero's film.

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