The holy saints and constellations

our main character a normal highschool graduate suddenly died and reincarnated into an unknown world and is trying to figure out what his role in his new world is.the description being in a world filled with 12 constellations beings seen as Gods and bless living things as the 12 constellations and their chosen holy saints potecting our so called realm from sudden judgment , or D-Day caused by an unknown reason causing destruction upon our cities and land caused by unknown creatures like a mythology or fantasy movies or games coming out of so called portals aka dungeons and the endless towers in each 195 countries, and the world thinks its time for a hero to emerge and save us from potential extinction.