The front line, Northern Seventh Defense Line.
Sea City.
Once, this place had been one of the largest port cities in the north. Countless people had lived and multiplied in this vast steel jungle. Gantry cranes in the shipyards had roared day and night, chimneys in the heavy industrial districts had belched plumes of smoke all year round, and the long steel dragons of rush-hour traffic could stretch for a full three kilometers.
But now, Sea City was dead.
Or rather, only half its carcass remained.
Four years ago, on the day the world became gamified, disaster had erupted without the slightest warning.
An abyss-like rift had suddenly appeared. The enormous crack that spanned east to west had torn Sea City completely into northern and southern halves, and the rift extended from the surface all the way down into a lightless, nethermost depth, varying in width from a few meters to several dozen.
Immediately afterward, a gray-white fog carrying a nauseating aura of deathly stillness had seeped up from the depths of the rift like a viscous liquid, slowly spreading in every direction.
Before long, inhuman howls had come from within the fog, and all kinds of system monsters had crawled out in swarms.
The garrison on the northern side had used flesh and blood to force the battle line to hold steady, but on the southern side near the sea, they had only had time to mobilize every ship and urgently evacuate large numbers of civilians by water.
As more and more monsters flooded the streets, in those early days when large quantities of modern weapons were gradually failing and system abilities had yet to be understood, humanity simply had no time to organize an effective counterattack.
It was not that they did not want to clear them out.