After the events of San Francisco, he found himself being dragged alongside other refugees. Unfortunately for him, and others, the lingering tether to the pact that bound entities to their avatars had side effects.
He realized his innate ability to make machines work for him, his ability to seemingly understand advanced tech like it was second nature. He soon found work, due to his impressive engineering talents, abroad trade vessels. After a few months he realized he would soon fall in the same routine as back on Earth - as such he decide to build himself a mechanized armor suit and try his hand at mercenary work. Hopefully see the Solar System, anything to escape the mundanity of his previous life.
His early days of playing Warhammer 40k provided an anchor for his mind, as such he made the mech suit to resemble one of a space marine and took the identity of Horus trying to play up this character.