Fans of the sci-fi animated superhero film "Big Hero" have been waiting to learn more new details about what the upcoming sequel, titled "Big Hero 7," will be offering. New reports reveal that it may feature Tadashi.

According to the latest buzz on the wire, Tadashi might come back as Sunfire on the upcoming film. Plus, X-men may have an appearance of some sort on it. The iconic comic book writer Stan Lee is also intrigued by the planned crossover.

Stan Lee expressed what he thought about the crossover in an interview with Toronto Sun. "After 'Ant-Man,' we're going to start playing around with 'Doctor Strange, the 'Black Panther,' the 'Inhumans,' and then we have to come back for 'Guardians of the Galaxy 2,' 'Big Hero 6,' the 'Avengers,' 'Captain America'...I don't even know how they decide what to do next, because every one of them is so exciting and the public is waiting for them," he revealed.

Fan theories suggest that there is apparently a long history between Sunfire and the X-men. If that turns out to be true, then it will most likely be unveiled and explored more on the "Big Hero 7." The theory further notes that just like the other X-Men, Sunfire was also recruited by Professor X in the wake of his exit from Big Hero 6. So, Sunfire teamed up with the other X-men to fight against the most vicious enemies like Moses Magnum.

There are also reports that say Tadashi did not actually die in the first movie. His return in the sequel might even be his transformation into a main villain that Hiro must defeat. However, Hiro's plan to fight against Tadashi's villainous side could also mean saving Tadashi's life.

There has been no announcement for "Big Hero 7's" premiere date, but it might hit theaters in the first quarter of 2017.