Hiro Takachiho was born a child prodigy with a super-genius intellect. The son of wealthy industrialist Tomeo Takachiho and Maemi Takachiho he was raised in the rich Tokyo suburb of Yoga, City of Setagaya. His parents recognised their son's intellect at a early age, he was in pre-school at age 3. Hiro is one of the world's most brilliant child prodigies and was accepted into the private Tesuka Advanced Science Institute. It was there that young Hiro's aptitude for invention was discovered.
Hiro is a smart genius whose father died when he was young. To partially replace him, he created Baymax, a robotic bodyguard. He was also a huge fan of Japan's greatest known hero, Sunfire.
When Big Hero 6 (Japan's official super-team) began to form, Hiro was drafted. He refused initially but after an incident wherein his mother was held hostage and BH6 rescued her Hiro reluctantly joined to prevent Everwraith from slaughtering millions in downtown Tokyo. During the battle, Big Hero 6 was joined by Sunfire, Japan's premiere super hero and a mutant with the ability to super-heat matter into plasma, who was instrumental in the Everwraith's defeat.