Shadow

In a world where demons come into the human world to cause havoc one teenage boy took it upon himself to protect his world, with the demonic power he inherited from his father and the help from his younger sister how will he pass through all the hardship? As time starts to tick down to when the demon king comes to the human world to take it over after all his subordinates fell to the hands of his foe, how will the demon hunter face off against him? How will he win against his brother?