Robert Callaghan, better known as Yokai, is the head robotics professor at the San Fransokyo Institute of Technology and mentor to Tadashi Hamada in Disney’s Big Hero 6. Professor Callaghan was a world-renowned scientist, praised for his innovations. He became a silent and masked villain after losing his daughter in an experiment. His only goal became to seek vengeance with an army of microbots at his command. In his mind, Yokai doesn’t see himself as a villain, because the tragedy left him with a hardened heart and he swore to have revenge, but he descended into madness.
