Big Hero 6

Hiro Hamada is a 14-year-old robotics genius who lives in the futuristic city of San Fransokyo, and spends his time participating in back-alley robot fights. His older brother, Tadashi, worried that Hiro is wasting his potential, takes him to the robotics lab at his university, where Hiro meets Tadashi's friends, GoGo Tomago, Wasabi, Honey Lemon, and Fred, as well as Baymax, a personal healthcare companion Tadashi created. Amazed, Hiro decides to apply to the school. He presents his project—microbots, swarms of tiny robots that can link together in any arrangement imaginable—at an annual exhibition to gain admission. Professor Callaghan, the head of the program, is impressed, and Hiro gets in. When a fire breaks out at the university, Tadashi rushes in to rescue Callaghan but the building explodes and both are killed. As a result of losing his brother, Hiro secludes himself from others.
One day, Hiro accidentally activates Baymax. Baymax follows one of Hiro's microbots to an abandoned warehouse, where he and Hiro discover that someone has been mass-producing Hiro's bots; they are attacked by a masked man called Yokai, who is controlling the bots. Realizing this man has stolen his project, Hiro decides to catch him and upgrades Baymax with armor and a battle chip containing various karate moves. After Yokai attacks Hiro, Baymax, GoGo, Wasabi, Honey, and Fred in a Mitsubishi Minica Toppo, the six form a superhero team.
The group discovers that a former lab of Krei Tech, a prestigious robotics company, was experimenting with teleportation technology. The test went awry when the human test pilot vanished inside an unstable portal. Yokai is revealed to be Professor Callaghan, who explains that he stole Hiro's bots and used them to escape the fire. Realizing that Tadashi died in vain, Hiro angrily removes Baymax's healthcare chip, leaving him with only the battle chip, and orders him to kill Callaghan. Baymax loses all of his softness, and develops a threatening, evil