He was a physiological disaster. At 4, when the quirk manifested, his heart almost exploded. The doctor's performed immediate open-heart surgery the very same day and the boy was able to live another day. Unfortunately, because of his quirk, he was labeled as a walking, ticking time bomb. His parents had to tend to his health, devoting a lot of their time and even hiring full-time assisted living to monitor him. While he could walk, talk, and do things any other normal kid could, Hiyoshi was still forced to be dependent on others.
As he got older, his power grew with him. Whenever he was by himself he took advantage of every minute to learn about what he could do and be capable of. He learned that his body had been adapting to the massive increase in temperature and the cell manipulation. Soon, Hiyoshi could control the heat and blood himself through excruciating trial and error. He was certain that even though he looked normal and lived among superhumans, this quirk was abnormal, to say the least.
Not too long into his preteen years, he was riding in the backseat with the nurse who helped take care of him. As the sun was dwindling, so were her eyes as her hands slowly steered the wheel into the opposite side of the road… There was barely anything left after the semi hit them head on. Hiyoshi, however, was covered in what looked to be red armor before it sank back into his body, revealing that he was unscathed as everything else around him was in decay.
After that, his life had become even more difficult and dependent. After spending a whole year in quarantine at a science lab, the prestigious school UA had caught wind of the boy, deciding to take him in as a student to both hone his power and hopefully provide him with a more healthy lifestyle/environment (much to his parent’s and the doctor’s chagrin. They had fought tooth and nail just to keep him in quarantine).
Now, Hiyoshi resides as a student at UA High, learning rather quickly and blowing through a lot of exams. The trauma had been pushed aside…