During a defensive battle, although there are many classic cases to refer to, manpower is sometimes limited, and demons are no different. In conditions of extreme inequality, turning the tide in a defensive battle is nearly impossible - it all comes down to how long you can drag it out.
The gates were breached, but Batman did not panic. Instead, he seemed to breathe a sigh of relief, for he knew that the next phase of the battle would be his turn to dominate.
The Rotting Heart General had not really taken this riot-suppression operation seriously. In his view, these enslaved miners couldn't possibly fight back. The innate gap between their races was glaring. Those naturally weak miners could not possibly make any ripples.
But to his astonishment, the battle raged on for two days and nights. The Rotting Heart General was infuriated. He had just promised His Majesty Beel that his troops were ready to fight at any moment, destined to be the sharpest sword on the battlefield. Yet suddenly, there was chaos in his own mine, and his well-trained elite soldiers were not able to defeat miners?!?
The fact that the Rotting Heart General could take over the second largest mine proved that he was not incompetent. He understood that if something unthinkable happened, there must be some secrets he was not aware of.
So, he did not hurriedly throw the commander into the magma. Instead, he reviewed this mountain-attacking battle thoroughly from start to finish and discovered a skilled master on the other side.
Being a general, the Rotting Heart unquestionably understood strategy and tactics. Like the saying goes, outsiders watch the show while insiders are aware of the details. Just from the initial two rounds of probing and attacking, the Rotting Heart knew that the person on the other side had definitely fought in major battles before.
What he didn't know was that Batman had already obtained the answer in advance. In the war he referenced, almost every form of adversity occurred - more than once - with various countermeasures, some effective, some ineffective, and some downright miraculous.
All Batman needed to do was summarize a bit, add a touch of localization - or maybe not even that, because no matter how weak the demon miners might be, they were still much stronger than humans.
The saying goes, "with a hammer in hand, everyone looks like a nail". Holding the answers, Batman was extremely disappointed with the so-called elite demon troops.
Having discovered the high proficiency of the other side, the Rotting Heart General guessed that this might be a conspiracy by other Demon Lords. They secretly sent people into the mine to incite war, aiming to mess up Beel's war preparations. The opponent's intentions were sinister.
Having realized this, the Rotting Heart General knew he could not underestimate the enemy. It was highly likely that they were as battle-hardened as he was. So, he immediately took over command, just as the demon soldiers had begun their entry into the mine.
Once inside the mine, they were a bit dazed. In front of them were dozens of diverging routes, each and every one unguarded. The slave miners who had previously been aggressive had completely disappeared, leaving the whole mine eerily quiet.
Upon sharing this situation back to base, the Rotting Heart General was also somewhat puzzled. When he took over the mine, he received a rough map from the previous owner.
The mine had been exploited for thousands of years and had been handed over to dozens upon dozens of generals. Everyone mined where the ore was abundant, without considering the layout of the routes and hence without a detailed map.
Generally speaking, nobody had ever considered a miners' rebellion, so they were very careless. The problem fell onto the head of the Rotting Heart, and the best solution he could think of was to have a veteran miner guide the way.
Unluckily, all the experienced miners who were most familiar with the Central Plaza were now in the Central Mine.
The previous decision to drive all the miners into the mine to work had backfired. Otherwise, he would have been able to find a few veteran miners in the dormitories. Now, he couldn't find a single person to guide the way.
Without knowledge of the route, they still had to plow ahead because they had plenty of troops. Thus, the Rotting Heart decided to split the troops into three and first explore the three central passages.
As soon as they entered the passage, a problem arose. The largest Heavy-Armored Demon couldn't fit through.
The tunnels were designed for miners, so they wouldn't be wide enough for soldiers to invade deep into the mines. The further in they went, the narrower the path. Halfway in, the heavy-armored soldiers got stuck.
The tallest demons in the mine, the Magma Demons, were only five or six meters tall and could stoop to pass through the three or four meter high tunnels. However, the massive demon soldiers, who were nearly ten meters tall with their armor, could not walk inside the tunnel at all.
The demons skilled in magic attempted to widen the tunnel. Initially, it worked quite well as they successfully passed through several tunnels.
On the subsequent journey, covering hundreds of meters of the tunnel exhausted all the mages in their team. This method of expanding a meter with every step was simply a waste of mana.
The widened tunnel was about several hundred meters, but each and every tunnel and passage was roughly of the same size, some even smaller. If they entirely relied on mages to expand the passages, even if the best Magic Knights under Beel's command came, it would hardly be effective.
So, the Rotting Heart had to abandon the plan of sending heavy-armored soldiers into the mine and instead assigned the small sized, light-armored demons to enter.
While these smaller demons were small in size, they possessed great strength and sophisticated equipment. In a head-on battle, there was virtually no hope of victory. However, no one faced them head-on.
In the first tunnel, the leading team did not get very far before smoke drove them back. The enclosed space and sudden thick smoke in the tunnel did not bother many demons since they didn't need to breathe or could hold their breath for a long time. But the problem was, the smoke carried spores in it.