Humans call them "calamities"—the unknown, destructive creatures that suddenly appeared on earth. To challenge these calamities, the zodiac gods awakened 12 humans known as saints. But there was one more that awoke—unchosen but the greatest hero of all: Geon Lee. His allies betrayed him and left him for dead, but now, 20 years later, he's more powerful than ever and ready to teach his fellow "saints" a lesson they'll never forget.Twenty years. For twenty long years, the thirteenth saint Lee Geon was trapped inside the Tower of Demons after being backstabbed by twelve of his allies. These twelve "saints" were warriors chosen by the twelve zodiac gods to defeat mysterious monsters called "calamities" that were massacring the planet. Though no god had chosen Geon as a saint, he became the mightiest of them all, which made him a hero... and a target. But now, Geon has brawled his way out of the tower, and he's back stronger than ever. All that's left is to exact brutal payback on each of the saints, but none of these powerful beings will go down without a fight. Will Geon be able to stay in one piece while achieving the divine revenge of his dreams?