Systemless Swordsman in a world of Systems

Having reached the pinnacle of the Murim world, Jagak Hou, leader of the Murim alliance, lead a charge towards the Heavenly Mountains, home of the Demonic Cult. Following weeks upon weeks of restless war, he came face to face with the Heavenly Demon herself. After a battle that split the heavens and shattered hell, Jagak was heavily injured and the Heavenly Demon had come out on top. Seeing that he could not overcome the Heavenly Demon, he decided to give his life in exchange for hers in Mutually Assured Destruction. Once he came to, he became an infant in a different world. This world was populated with systems - complex algorithms powered by Mana (an energy similar to Qi) assigned at birth that allowed humans to use Magic - a way of altering the laws of physics using Mana. Jagak was, of course, fascinated by this mystic power and wished to study it, however there was a massive problem with that, being that he was the only human in this world without an assigned system, meaning he couldn't use Magic. Faced with an uncaring, cold reality, how will this former master survive as the only systemless Swordsman in this world of Systems...?