Even before they went in, Yemu had already warned everyone that what they were about to see would be extremely bloody, so they should prepare themselves mentally. But when Ayala, Lillilu, and Kuromu stepped inside and saw the scene before them, they still felt a deep wave of discomfort.
What appeared before their eyes was a massive semicircular space. Rows of wooden crosses were nailed into the surrounding walls, and hanging from them were all kinds of stitched-together corpses, half human and half animal. On the ground stood a dense forest of glass containers filled with glowing green liquid, along with all kinds of organs and animal tissue.
From a distance, it looked exactly like the secret laboratory of some mad scientist.
Even more chilling was the fact that these so-called corpses were still alive. Their chests were rising and falling, and their eyeballs were still moving.
No wonder Kuromu had called them zombies.
In fact, if one listened carefully, it was even possible to hear hoarse voices coming from their mouths.
"It hurts... it hurts..."
This was a hell even more horrifying than Levels 1 through 6 of Impel Down.
Even Lillilu, who had seen the world alongside Rocks, was wide-eyed at this moment.
"What the hell is this!?"
She looked at Yemu, hoping he could give her an answer.
"I don't know either. I took a quick look further in just now, and it seems there's more than one place like this. There are other spaces connected beyond this one, so maybe..."
Yemu did not finish the sentence, but everyone already understood.
That meant there might be even more places like this deep underground, farther inside the cave.
There were nearly a hundred of these zombies hanging on the walls in this cave alone. That was not even counting all the organs and tissue. No one could say how many victims there had been inside.
"I'm going to keep going and take a look. Maybe I'll find some answers. Just in case, you should head back up and rest first. Once I figure out what's going on, I'll come find you..."
But as soon as Yemu finished speaking, Ayala shook her head.
"Yemu-nii-san, I want to go with you..."
Seeing that Yemu was about to refuse, Ayala hurriedly explained.
"I know you're really strong, Yemu-nii-san, but..."
At that, Ayala glanced around at the horrifying scene before continuing.
"Judging from what this place looks like, something unexpected could happen. I might be able to help you..."
Lillilu nodded as well.
"If there's poison gas or something, bringing Ayala along might help with detoxifying it..."
"All right, then."
Yemu felt that made sense. Judging from the horrifying scene in front of them, there might really be some terrifying mad scientist lurking in the depths of this cave. In a direct fight, Yemu naturally had nothing to fear, but tricks outside of battle were much harder to guard against.
"Then let's do this. Ayala, go back up with Kuromu first and get some supplies from the box. Gas masks, antidotes, food, anything like that. Once everything's ready, we'll take a proper look at what secrets are hidden in this Level 5.5..."
"Okay!"
...
About half an hour later, Ayala returned with Kuromu carrying a large bag.
After everyone put on gas masks and took some anti-poison pills Ayala had prepared, they began exploring the underground Level 5.5 in earnest.
Just to be safe, Yemu took Ayala's and Kuromu's hands, while Lillilu lay across Yemu's shoulder.
"Be careful. Judging by how neat and orderly this place is, people definitely come here often. Don't leave any traces behind."
"Okay."
At that point, Yemu also explained why he knew this place existed.
"All I know is that this space was created nearly a hundred years ago by a prisoner locked up in Impel Down, using the power of a Devil Fruit. I originally thought no one in Impel Down should know this place existed... but it looks like I was wrong..."
Only then did the others understand.
Still, no one kept pressing Yemu about how he knew all this, because the hellish, nightmarish scene before them had everyone's full attention. No one had the spare focus to think about anything else.
As they moved forward, they passed through that horrifying hellscape.
Another dark tunnel entrance appeared before them, with no visible end in sight.
By now, Yemu had roughly guessed the layout of Level 5.5.
"It looks like the ability user who created this place didn't hollow out the entire Level 5.5. Instead, they dug out large spaces like this and linked them together with tunnels. Let's keep moving. Whatever happens, don't be afraid. Just remember that I'm here."
"Okay."
Feeling the warmth of Yemu's hand, Ayala, who had been tense, relaxed at once.
After walking for another ten minutes or so, they came upon another space exactly like the previous one.
But unlike the first chamber, this one was filled with all kinds of large iron cages, and inside them were all kinds of animals.
Though calling them animals was not entirely accurate, because most of them had certain human features.
More notably, their eyes looked just like those of the army wolves they had seen in the Freezing Hell, ringed with ripple-like circles.
The moment they saw Yemu and the others enter wearing gas masks, the animals immediately turned savage, as if they had just spotted some delicious prey. Their eyes turned blood-red, thick saliva dripped from the corners of their mouths, and they began roaring wildly.
"Shut up!"
Fortunately, Yemu released his Conqueror's Haki in time, and the world fell silent again.
Seeing that, Yemu had already guessed something and said to the others, "Looks like the experiments here are related to those Jailer Beasts we saw when we came down into the Beast Hell of Impel Down..."
"Mm."
"Let's keep going and see what else is below..."
It did not take long for them to reach a third massive chamber.
But unlike the first two, this one was as cold as the Freezing Hell.
Dozens of half-human, half-animal corpses were frozen throughout the entire space. But this time, everyone could clearly see that unlike the half-human, half-animal zombies in the first chamber, these corpses showed no signs of being stitched together. Instead...
Lillilu was the first to react. Looking at those corpses in prison uniforms, each one half human and half animal in a different way, she said in a low voice, "These are Zoan Devil Fruit users?"
Just then, Yemu suddenly sensed something through his Observation Haki. Without wasting a second, he said to Kuromu, "Someone's coming. Let's hide first!"