Batman, a genius on both the strategic and tactical levels, was the chosen one who descended into Hell to save the demons.
The script he should have received was to use Seven Mountains Mine as his first base, steadily expand outward, use the banner of purging the ruler's side to force Belial to drive Schemer Schiller away, then gradually devour all of Belial's territory and continue conquering until he unified Hell.
But as the saying went, even the cleverest housewife could not cook without rice. When someone's luck was bad, even drinking cold water could chip their teeth.
Batman had only just acquired a portion of Belial's territory with poor strategic positioning and few resources when he was besieged by every nation in all directions.
More frighteningly, these nations were no longer demon kingdoms stuck in the Middle Ages. During the time Batman had spent unifying Seven Mountains Mine, the other Schillers who had gone to interview with Demon Lords had not been idle either.
The vast majority of Schillers had successfully earned the Demon Lords' trust. Quite a few, like Schemer Schiller, had even driven wedges between the Demon Lords and all their original confidants, seized absolute power over life and death, and begun sweeping reforms.
The methods Batman knew, the Schillers knew as well. Some Schillers even had more experience with infrastructure than Batman did, after all, he came from a country that had once been even more impoverished.
The various nations of Hell were not in particularly good shape, but several of the larger nations were actually fairly wealthy. They had complete and systematic technology trees, as well as a group of reasonably capable mages. Though the quality of their soldiers could not compare to modern armies, demons' naturally superior physiques made up for their lack of