Hiroto was born to a happy earth bending couple in the Earth Republic. Daichi and Akemi were overjoyed when Akemi gave birth to Hiroto, and with them already having a twelve year old fire bending daughter named Aiko, they assumed that Hiroto would also be a bender. They just didn't know what kind. As Hiroto grew up, he would always watch in amazement as his parents and sister used their bending powers. They would often try and get him to use his bending powers as well, but it was no use as Hiroto wasn't showing any signs.
It wasn't until Hiroto turned six when he finally showed signs of being an air bender. Accidentally knocking Aiko down with a ball shaped blast of air when they were playing around. Not long after that, Aiko applied for citizenship in Republic City when she was seventeen years old. After Aiko left the Earth Republic, Hiroto was never the same. As he had often relied on following his sister around the house and for guidance, Hiroto felt lost and with that he became quiet, choosing to observe things.
Hiroto was a very respectable person, even when he was growing up. He never got into trouble, and would always ask for permission, even for the smallest of things. After Hiroto turned ten, he asked Daichi and Akemi to help him hone his bending powers. But since neither of them were air benders, they couldn't help him on a proper level. With the help of Daichi's friend who was an air bender as well, Hiroto learned how to hone his powers after three years of lessons.
After Hiroto's three years of lessons, he spent the rest of his time focusing only on himself. On his sixteenth birthday, Hiroto made the decision to apply for citizenship in Republic City. After saying his goodbyes to both Daichi and Akemi, he left the Earth Republic. When Hiroto arrived in the Republic City, he was reunited with Aiko.