The Last One Standing

It happened unexpectedly!! A sudden and swift attack that no one saw coming, that no one was prepared for!! The attack of demons that poured forth from the depths of hell, nearly wiping out the entirety of the human race. That was 1500 years ago, but the fight with the demons rages on to this very day, neither side yielding an inch. Mankind continues to struggle for survival, but the demons grow stronger and the human population steadily shrinks. This is the story of a young man name King Tatsumi, an aspiring warrior who grew up wanting to fight on the front lines against the demonic horde. Will the demons finally wipe out the rest of humanity and finish what they started all those years ago? Or will it be the humans who have the last laugh, who have the final cheer of victory? Which race will be the last one standing?