Hiero has many versions and alternate realities to his life. These are a couple prototypes and some full on work that the character has actually been in.
Initial Island of DoomParticularly in this roleplay, this was a more primal Hiero. In the reality of Island of Doom, each character was intoxicated by the odd mist and air particles.
The air particles just so happened to make Hiero jumpier and some what crazier. This is shown as he has little to no concern for anything in Island of Doom until later as the plot develops.
As Hiero got off of the island, he became much like his canon counter-part and slightly humble. He was only sixteen and still suffered from depression due to his mentor's death.
Earth Sided Chronicles
(Serious warning, this streches on from a story that hasn't even been fully developed yet.)
In the Earth sided Chronicles, Hiero is no longer a Fire-Elemental hero. He has become a rogue who does things only for himself and has no care or compassion to what others feel. This side is a what if story that stretches from the hidden story about Hiero's parents and what if he found out about it.