Just as Leon had expected, the battle ended without a single casualty on the human's side. It was hard to tell, but more or less four million monsters died in four hours. Once again, everyone celebrated such an astonishing victory, but once again, Leon didn't feel like celebrating.

"You are frowning too much..." Betty said. "What will people think if the hero of this battle acts like this after such a victory?"

"Still... I can understand why Leon is worried." Sasha said. "He learned a very convenient skill in a crucial moment; it is very suspicious that his luck is that good."

Leon didn't tell them about the voice, but Sasha was smart enough to figure it out that something was off. In any case, there was no time to stop and relax; they still had to fight to protect three other cities.

Regardless, this time Leon and his zombies ended up winning the battle almost alone. So, Leon decided to take the dragons' hearts for himself. He wondered what would happen to those monsters' hearts once they become zombies, so Leon opened a T-Rex that had died again after becoming a zombie. As expected, the skill wasn't that convenient; the monster's heart melted. Not only that, but the zombies' corpses also rot in a matter of seconds after using all its juice.

"It is powerful, but it is also a very unpleasant skill," Betty said.

Leon could only nod, forcing dead creatures to fight was something beyond unpleasant. Still, Leon could easily use that skill to almost seal the dungeons if he defeats a few bosses and turn them into zombies, they could easily kill other bosses and monsters that the crystal will spawn. That would be very convenient for Leon, but would that help the world? In some sense, yes. However, stopping all the monsters by himself wouldn't make the human race strong. Billions died four years ago because humans were weak and relied too much on tools. Even if Leon seal all those dungeons, no one can say that other dungeons won't appear and liberate thousand of dragons on Earth again.

"I can't rely on this skill too much… this won't make me the only lazy, but the whole world will become like that if I'm not careful."

Leon and the others had some time before the monsters could reach Rio de Janeiro, so he decided to sleep in the chopper Tom brought, while they transported him to the next city. Once again, Leon left one hundred zombies behind and made one thousand of them move to Rio de Janeiro.

Just like Leon saw in the movies, Rio de Janeiro was a beautiful but at the same time, a city destroyed by bad governments and militiamen. The natural beauty of the city was a sight for his sore eyes, but he didn't have time to appreciate it. Anyway, this time, his zombies arrived in the city before the start of the battle, so he didn't have to summon his skeletons. Once again, the battle ended without a single casualty. While Leon observed the zombies and the railgun doing all the work, he started to think.

"I didn't learn this skill by coincidence… even though I also have the scythe, which grants me some useful skills, it is nowhere as near as powerful as the skill to summon zombies. Considering what that skill could do at this level and its potential… there was a chance that a boss shouldn't drop a tome of such level, the T-Rexes aren't as strong as the three-headed earth dragon after all. So, the owner of that voice dropped the tome? If yes, why he didn't do it sooner? What is that person's goal? I certainly didn't imagine that voice…"

With so many doubts, Leon didn't want to use that skill. Humanity needed to struggle more to fight and get stronger in case something like what happened four years ago repeats itself again. Still, he needed that skill to make Atlantic Free Nation his allies. If he holds back and lets someone dies, Leon would end up putting doubts in their minds, and a partner full of suspicions wouldn't be so cooperative.

The next two days, Leon and the others succeeded again. Atlantic Free Nation survivors became allies, and the day had been saved… however, Leon didn't feel like his job was done. While the survivors were dealing the monsters' corpses most with the Dragons' hearts that Leon wanted, he searched for some very specific equipment, which was, oxygen tanks, a mask to let him breathe in high altitudes and winter clothes.

"Why do you want that?" Betty frowned.

"I want to see this continent from above…" Leon said. "I need to confirm something."

Even Sasha frowned since she had no idea what Leon wanted to confirm. Leon also bought a map that showed them the locations of all dungeons in South America. After equipping those items, Leon created an earth platform, and they flew upward.

Leon thought he would be able to see the whole continent if he tried to fly a little high, Leon indeed managed to see a good portion of the continent surface. Still, when they reached thirty kilometers of altitude, the temperature got so low that they had no choice but to retreat. Besides, even though they were using a platform that was being controlled by Leon. It was still scary flying so high.

It looked like Leon would have to borrow some astronaut clothes if he wanted to confirm those things in his mind. Regardless, Leon managed to confirm at least one thing. From that height, he saw the trail of destruction the monsters left when the dungeons break happened. For some reason, after leaving the dungeon, the monsters choose the shortest path, not toward the cities, but to join the other monsters.

"Whatever caused the dungeon breaks, it also made the monsters reunite in order to make them attack all cities at the same time but in different periods… There's no way this happened by chance. Someone caused this… but why?"