According to Stan Lee and Disney it has officially been confirmed that
there will be a Sequel to Big Hero 6. There has been talk that Tadashi
is going to turn out to have survived the fire but he is not going to
be the Tadashi we knew during Big Hero 6. He is going to end up
being the villain in the sequel and he is going to have fire powers.
It is also said that in the Original Big Hero 6 Hiro's brother was
thought to be dead in the fire but his brother turned out to have
survived the fire and became a villain known as Sunfire. Stan Lee
said that Disney is most likely going to keep to the original story
and make Tadashi a villain in the sequel of Big Hero 6.
My reaction to this :