Profile of Hiro.
No one was aware that Hiro was such a troubling fledgling because he was born with a twin branched soul, one part of him normal Hiro and the other a reincarnated powerful Fiend (demononic spirit). After Hiro was cast out from many villages due to his behavior Big Master recognized the evil half of him and sealed it more throughly inside the young dragon. Hiro has since been in training to control and harness the power of this evil half of him by Big Master since.