Sinful Paladin

A swordsman from the East, burdened with some kind of "original sin", was accidentally saved by the remaining "holy light" in the Western world when he was about to die, but he was also infected with the strange "power of sin". He became a special "Sin Karma Paladin" - carrying the Holy Light, but able to absorb and transform sin karma for his own use, wandering on the edge of light and darkness.