Doomed Thunder
The vortex swirled faster and faster, turning into a blurry red mass. The few pieces of rubble that had lasted through the destruction of the city and the vortex were finally disintegrated into pieces smaller than dust.
A sparkling light spread out from the center of the vortex. The vortex turned into a glittering red galaxy and stabilized, completing the creation of the portal with a sky-rending tremble and the spread of incredible amounts of demonic energy.
The imposing city walls that had stood steady for ages crumbled in front of the energy emanating from the portal. It was a portal created through the sacrifice of an entire city and a horde of beasts. All of them were at the minimum of the fourth level. There were even several high level humans and beasts in the mix.