Zero

Zero (originally named Project: 00, but commonly referred to as Zero, or simply Z) is an artificial human project made by Hell in an attempt to build the perfect killing machine against Heaven.

After the completation of the project, the unexpected happened and Zero took a mind of his own. Somehow he managed to gain free will and tried to break away from Hell. Outnumbered, he was eventually captured and brought to an airship prison where he would wait until Hell could find a way to control him. There he was kept for a few thousands of years, resisting control, but hopeless about a chance to escape.

In December 21st, 2012 in Earth's calendar, a plan by an unknown party was set in motion. The ship in which Zero was being held, together with its entire fleet, changed their course to crash again Hell, but as soon as they reached the atmosphere, a dimensional rift was opened, making them rain against Earth instead. The crash was not enough to kill the tough hellings nor Zero, but something in the systems made Zero's memory reset. As the lands were taken over by chaos, he arose from the crash site, unsure of what was going on or why he was there. From there on, he could live only for his own survival, searching for survivors of the destruction and maybe to find something about his past - the only hint he had was a "00" mark on his shoulder, from which he decided to call himself Zero.