As the day passed, the child continued to work on the fourth floor. They placed alluring vines along the canopies and trees and ravenous snails within the water. The vine monsters blended in with the red trumpet vines, and the snail monsters became almost impossible to see in the water, which was becoming murkier and murkier due to the brown-green mana string circulating around it.

Congratulations! You have completed your fourth floor!

Present Creature Species: 23

Present Plant Species: 10

Present Monster Species: 2

With the fourth floor completed, your sub-dimension will now grow compared to your power.

As their sub-dimension expanded and the monsters settled within the fourth floor, the child thought about their dungeon, and realized they hadn’t really done everything with the one very important room in their dungeon, their core room.

It was empty, with only the pillar holding its core within the room, but the child knew it could not stay that way. They need to fix up the room and make it so that their core is protected, and they already have an idea of how to do this.

First, they increased the height of the core room from three metres to six metres tall. They made it so that the water level increased so that there were only around 20 centimetres of air within the room.

To protect their core, the child dismantled the pillar holding their core and created a mini-room within the room, like an upside-down hollow bowl with a small tunnel going upwards. The container was large enough to comfortably fit their room, and the tunnel was large enough to squeeze their core through.

Their core, a three centimetres diameter sphere, was pulled through the tunnel and into the room. It has grown. Their core. It was once one centimetre in diameter, but it has grown more every time they have gained a floor.

They settled their core into the very back of the room and condensed the container into pressurized ice to make the ice a lot stronger than regular ice and fused it to the ground. They pulled sand from the outside surrounding area through their floors and into the core room. They filled up the room and mini room with the sand, enough to completely cover the ten centimetres by ten centimetres long container.

Once they pulled their core into the container and condensed it into pressurized ice, the child started pulling sand from the surrounding area into the room. They filled the room so that the sand covered 20 centimetres of the ground and filled the container with sand.

With their core encased in a level of protection, the child continued on with building their core room. First, they created thirty long, solid pipes with holes going through them for all plants and corals to latch onto them. Then, once built, they strengthened them into pressurized ice rods that they fused to the edges of the room, creating rods that are parallel, horizontal, and vertical rods around the room, thick enough and abundant enough that they would cause any invaders to have problems moving down to their core even without any plants, animals or monsters stopping them.

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The child took grasping gel seaweeds and fan corals and made them grow along the rods and within the sand. With those placed, the child moved blue-ringed snails, grey oysters, and crystal krill swarms. Once they were moved and settled, the child chose a monster to protect their core.

They chose the ravenous snails, small enough to move through the crowded environment that was their core room and vicious enough to protect them from anything that came through the tunnel from the last floor into their core room. So the child pulled a good amount of the snail monsters from the fourth floor and made them their core rooms protector.

With their core room done, the child reviewed the new changes within their dimension. Like the last time their sub-dimension expanded, this time it only increased in height by about 15 metres, making their sub-dimension height 35 metres high.

As always, when their sub-dimension expands, the surrounding floors can be moved around. It’s not like the floors themselves, or the tunnels connecting them were changing, but it was like their sub-dimension would wiggle them around to make space available for more floors. And that was what it did this time, leaving almost all of the space underneath their dungeon core free.

This was when the child had their idea for their next floor.

A maze.

It was ideal for the child, especially with their new acquisitions of alligators and sharks.

Just as they were planning out the layout, they felt something enter their territory.

It did not feel like anything that had entered their dungeon before, and especially not an adventurer coming to their dungeon.

It looked like a woman, like a human … but it was not.

The being had the same body shape as the humans that they have observed. Two arms, two legs, and a head, and they were completely naked. Their fingers were clawed, and the hair on the woman-like being’s head was green and looked like seaweed. Along their neck were a set of gills, and the woman swam and crawled through their dungeon’s entrance like they were going wild.

As soon as they entered their first floor, they started clawing at everything they could touch, destroying the rooms and killing all of their creatures and monsters.

They quickly made their way to the first floor, and as soon as they went through the portal, they just went insane.

With a feeling of dread over them, the child watched as the being was five times as destructive to their second floor than their first and started making a bee-line to the next floor.

Oh, that’s not good. The child thought as they realized that this thing was probably after them somehow. So theft called all of the monsters they had on all the floors and got them ready for the assault.

The ice krill managed to damage the female-like being slightly, but the child could work with that.

As they crawled through the top portion of the third floor, the child used the alluring vine to grab and pull on arms and legs, attempting to dislocate or hurt the being before they managed to get back into the water.

But the being was too strong for that. Every time an alluring vine grabbed onto them, they slashed them away with their claws. It took four alluring vines at grabbing onto the being at once for one to dislocate their left arm. But that did not stop them.

They managed to get back into the water, and then the ravenous snails attacked.

Geared up with an intensity that the child hadn’t seen from them before, they attacked the being in waves, never letting up.

They had almost depleted all of their ravenous snails from both the third and fourth floor before the being died with a wretched scream from blood loss. The creature gave the child hell. It was not something that they had ever experienced before. It destroyed everything in its path, leaving their first, second, and third floors in shambles, with populations decimated and them having to clean up the mess.

In truth, this was the first time the child felt that their being, their core, was in danger.

While the woman-like creature left destruction in her wake, they did leave something behind other than damage and death.