Yokai (real name Robert Callaghan) is the main antagonist of Disney's 2014 film, Big Hero 6. He was the lead professor of the San Fransokyo Institute of Technology before becoming a supervillain. Driven by revenge, Yokai wishes to get revenge on Alistair Krei for taking his daughter from him.
Trivia
Callaghan is never referred to as Yokai in the film, but is in several merchandise.