In the Marvel universe, too, Deadpool’s style doesn’t seem to match. The character frequently “breaks the fourth wall” – a cinematic term for the character going out of his film to interact with the audience.
Deadpool could not suddenly appear in the scene where Captain America and Iron Man were fighting to warn the audience not to chew the popcorn too loud.
But there is still a way for Deadpool to appear in a Marvel movie in the future. Possibly a solo repertoire like Quicksilver in X-Men: Days of Future Past, coming and going like a bolt of lightning (literally), has a solo that excites the audience.
On the other hand, instead of wanting Deadpool to appear in the Avengers or X-Men, the audience should expect the opposite to be more feasible. For example, another superhero or mutant will appear in the Deadpool movie.
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