KOZA was a kid born in HZ63 district.
When he was young, his parents stole Yan Energy and sold it in order to survive, but Satan turned them into Yan Energy, and KOZA, who lost his parents suddenly, was forced to live on the streets. He silently vowed in his heart that when he has enough power in the future, he will save his parents and reunite the whole family again.
One winter afternoon, KOZA, who was starving and cold, broke into the bakery and stole bread when the bakery was about to close. Unexpectedly, he was caught by the boss and was severely beaten. After witnessing everything, an old man known as "Iron Tiger" decided to take KOZA back to the Iron Tiger Machinery Factory to take care of them. The two made a living by scavenging metal waste.
In the days of the machine factory, Grandpa Iron Tiger regarded KOZA as his son and taught him how to reshape scrap metal into various machines. At the same time, KOZA is constantly looking for ways to strengthen and bring back their parents. When making an engine, he realized how to convert thermal energy into mechanical energy. With an idea, KOZA began to try to apply this technology to thermal mecha equipment. After numerous experiments and failures, he finally succeeded in creating his own weapon.
Now, with strength and new equipment, KOZA is preparing to participate in the annual HELL RACING, and only wants to redeem the parents who were converted into Yan Energy... KOZA是出生在HZ63區的小鬼。
在他很小的時候，父母為了生存而偷取閻屴變賣卻慘遭撒旦轉換成閻屴，頓時失去雙親的KOZA則被迫流落街頭。他在心裡默默發誓，等未來擁足力量，一定要救回雙親，讓全家再次團聚。
某個寒冬下午，飢寒交加的KOZA趁麵包店要打烊時，闖進去偷了麵包，不料卻被老闆抓到，因而挨了頓毒打。一位人稱「鐵虎」的老人在旁目睹一切後，決定將KOZA帶回鐵虎機械廠照顧，兩人以金屬拾荒維生。