'Big Hero 7' release date update: Cast member hints at sequel; Tadashi returns as villain?

Will the rumored sequel to the box office hit "Big Hero 6," which is unofficially dubbed "Big Hero 7," have brother going against brother?

While Disney has kept mum on whether or not it will be making a sequel to "Big Hero 6," various reports have been popping up about the so-called "Big Hero 7," including a potential plot line and a possible new villain.

According to Movie News Guide, the main villain in "Big Hero 7" will be none other than Tadashi (Daniel Henney), Hiro's (Ryan Potter) older brother and Baymax's (Scott Adsit) creator.

While Tadashi appeared to have died in an explosion as he attempted to save Professor Callaghan (James Cromwell), theories about "Big Hero 7" suggest that the kind genius actually survived and was somehow turned into an evil being. Movie News Guide further theorizes that Tadashi will return as the villain Sunfire from the Marvel comics.

But while a plot line involving Hiro facing off against his beloved brother seems like an unwelcome prospect, the outlet points out that Disney is unlikely to deviate from its formulaic happy endings. In short, Tadashi will somehow return to being good. He and Hiro will reconcile and he will become the seventh member of the gang.

While Disney has yet to make any official announcements about its plans for a "Big Hero 6" sequel, fans expect that with the original film being such a success, "Big Hero 7" is practically inevitable.

This was corroborated by "Big Hero 6" actress Genesis Rodriguez, who played Honey Lemon, in an interview with Screen Rant last year.

"There's rumblings of something else happening," she said. "I mean yesterday I just saw that it's the third most grossing Disney animated feature, so this is huge for them. I doubt that they wouldn't want to do another one. It was a huge success," she added.

Disney has yet to release official word about a possible "Big Hero 6" sequel.