Big Hero 6 and that lovable yet fierce health companion, Baymax, will be making their way into Kingdom Hearts III.
Baymax will have a role in helping Sora traverse through San Fransokyo in Kingdom Hearts III.
A new world will be available for Sora to explore with the inclusion of San Fransokyo as one of the playable worlds. Within you'll be able to interact with the main characters, Baymax, GoGo, Wasabi, Honey Lemon and Fred. The overarching themes of both Big Hero 6 and Kingdom Hearts II are very similar in nature, so they're a perfect fit for each other.
The next installment of Kingdom Hearts has Sora, Donald Duck, Goofy, Micky and Riku returning so and going on many new adventures across various Disney themed worlds. In the third installment we'll get to see many more Disney IP's. The worlds within Kingdom Hearts III are said to be all new to the series, and might include IP from Marvel and even Star Wars.
The third installment will feature an older Sora as the playable protagonist who sets forth on a new adventure with his band of misfits in search of the seven guardians of light and the “Key to Return Hearts,” to stop Master Xehanort’s devious plan. Kingdom Hearts III will harness next generation console technologies to weave together an incredibly stunning universe full of both new and familiar Disney worlds. This game will conclude the series’ “Dark Seeker” saga.