Although the group was chased for a while, the number of water worms chasing them decreased eventually. Still, there were no signs of the dungeon. Moreover, the bottom of the sea was starting to get deeper and deeper, so Billy was starting to worry if the dungeons were at a level where the light of the sun couldn't reach… Even if they had super human bodies, things would get very complicated so deep…
Fortunately, Billy's fears were unfounded, and they eventually found a dungeon at a place light could reach, and the submarine could do as well. It was only fifty meters deep underwater…
"It appeared fifty kilometers away from the coast. I wonder why…" Kate said.
"I guess most people wouldn't be able to reach this far after fighting so many enemies," Lily said. "Without Billy's invention, it would be impossible, even for us."
Billy decided to stay quiet since he didn't invent the submarine. He just copied one. In any case, he made sure to use his magic to put a landmark there. It wasn't tall, but he put a long spear made of mana at the top of the coral. He could feel the energy even ten kilometers away, so it was fine.
"It wouldn't be better to clear one of the dungeons today?" Kate asked.
"While the entrance of the dungeon seems large enough, we don't know about things deeper," Billy replied. "I don't think that we will have to deal with a maze, but we should return after making some more preparations. We might also end up surrounded from the front and from the back if we don't get rid of some more monsters while we look for the dungeons."
Although he said that, Billy was itching by destroying that one… Still, it would be better to get rid of them on the same day since he had no idea what might happen if he didn't do that. Also, Billy would need oxygen tanks and regulators to help them breathe underwater… even with that skill, things might get too messy, and they couldn't afford to use so much mana. That being said, Billy was starting to wonder what his friends would think if he kept showing them those convenient things.
In any case, Billy decided to search for the other dungeons without approaching the coast, and much to his surprise, he found two others after heading North. It was hard to say if it was a fortunate coincidence or if someone had been sloppy on their job. On the afternoon of that day, Billy and his group also easily found two other dungeons down south.
"I guess this settles it," Kate said. "Still, how are you going to fight in there if we can't use the submarine?"
Three of those five dungeons truly had small entrances, so the submarine could cross the paths. Not to mention, it was also very like that the path would have some curves that would make the vehicle unable to proceed forward… so they would have to fight with their bodies alone.
"Let's return home. I will tell you guys how things will be once we get home," Billy said.
Billy told them the plan once they returned, but they didn't have a good time imagining that. In the end, Billy had to make an oxygen tank and a regulator to show them how it was done. While he didn't have much experience diving, he had enough for that kind of task. Moreover, he could control his buoyancy with Telekinesis. However, his friends couldn't. Use their bodies' strength to prevent going too deep as possible, but it would tire them out tremendously. After showing them that one could stay underwater for quite a long using a tank, he told them his idea.
"This is a magic item that gives you a chance to breathe underwater, but you need to breathe slowly and recharge the item with your mana now and then," Billy said. "By carrying this on your back, you will end up sinking, but you guys can use wind magic to prevent that."
"That will grant us some mobility, but how are we going to attack?" Kate asked.
"I suppose I will make some special magic crossbows as well," Billy replied. "It has been a while, but I should be able to make something even better than before."
It had to be better. Otherwise, the projectiles will lose too much time while they fly, and they wouldn't pierce the enemy's bodies. Usually, it would be better if they had a few days to practice all that, but Billy thought that they didn't have that luxury. They would have to learn as they go.
After giving his report to Natalie and Sarah, Billy wondered what he should do… Natalie wanted to go and fight the monsters, even if she had to use crossbows instead of swords. Still, Billy didn't want to leave Sarah alone with the kids.
"Billy… I am completely recovered," Sarah declared. "Nothing will happen during the day, and the kids have their pets. Until now, not a single accident happened, even when we were away, so why do you think something will happen now?"
"Well, because of Murphy's law… No, forget what I said," Billy said. "You are right… I am overthinking it."
"Yes, you are," Sarah said. "Besides, I already learned Mana Dominion, so I will be aware if something is about to happen."
"Roger that, you will hold the fortress while we are gone," Billy said.
In a sense, Billy and his friends were the ones who had to worry since if something goes wrong, they would be surrounded by hundreds of enemies in an underwater cave with only one exit. Not only that was scary, but it was also dangerous.
In any case, before the mission could start the next day, Billy also made some Google to help everyone see well underwater. Billy even added some flashlights on those in case the weather gets rough, and the visibility gets bad inside the dungeon.