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?

Keimanga

The Return of the Disaster-Class Hero Chapter 132