“The bats in these tunnels are all believed to be Tokyo giant bats. They hunt for insects in the forest around Kanto during the day and return to the caves at night. They have few natural predators and have never been recorded to be a threat to humans. Also, it is unknown if they have any communicable diseases.”

“See? It’s fine,” Satoru said.

“…the caves of area 23 of Old Tokyo are believed to be home to ten billion bats. The guano of Tokyo giant bats is food to many animals, and have transformed a formerly barren environment into a thriving ecosystem. Tokyo giant bats are named on account of their large size, but it is doubtful that they are descendants of Ogasawara giant bats. This is based on the premise that the megabat suborder, which includes the Ogasawara giant bats, do not live in caves and do not use echolocation. The other theory is that Kikugashira bats, of which there are many in the Kanto area, have evolved larger bodies…”

The fake false minoshiro continued to drone on and on. It seemed that unless it was asked a new question or explicitly ordered to stop talking, it would just keep going on endlessly.

“…are the insects that live off of guano venomous?” Satoru asked.

“The majority of insects here are non-venomous, and also do not bite humans. The exception is the cave botfly. Due to the unending supply of guano, cave botflies have no need to search for food and therefore have lost the ability to fly. They spend their lives as maggots and lay eggs in the soil. However, they still have sharp mouths and can bite people on the hands or feet. It is unconfirmed if they are venomous, but the wounds they inflict can become infected in unclean environments. In addition, the secretions from their mouths can, on rare occasions, cause allergic reactions…”

“Alright, alright. That’s enough,” he silenced the fake false minoshiro. “It’s these big maggots, right? Well, we just have to watch out for them. In any case, we have to go now. There’s not much time.”

I squeezed my eyes shut and stepped onto the disgusting, wriggling mass of insects and guano. My boots squelched and I sank in up to my ankle. I shuddered violently and goosebumps sprouted all over my body. This more or less managed to distract me from the insects flying so thickly around us that I felt like I was in a sauna.

After a while, I felt solid rock underneath my feet again and was so relieved I thought my knees would give way.

“Now I know what you mean when you said that underground Tokyo was hell.”

Kiroumaru smiled. “We’re still in heaven right now.”

It was slightly cooler once we left the bat cave. I was thankful for this at first, but soon started feeling clammy. This was the first time I realized how uncomfortable it was to be cold and damp at the same time.

Kiroumaru, who was still leading the way, didn’t seem to be bothered by this environment at all. I remembered that queerats were originally cave-dwelling creatures and felt encouraged by his presence. But then I remembered that the ones chasing us were also queerats.

“You said you’ve been to Tokyo before?”

“Yes.” Kiroumaru replied, sounding somewhat reluctant to discuss this.

“So you know this area well? Why didn’t anyone build colonies here? The caves would have been empty in the beginning.”

“My species sent many to tackle this land, but none attempted to live here,” he answered solemnly. “There were too many unpleasant occupants already here. Like I said before, I lost a third of my soldiers just exploring the area.”

I wondered if I should press him about it, or ask the fake false minoshiro about the unpleasant occupants.

“Where to from here?” Satoru asked before I could say anything.

“27 degrees northwest. Your route has been largely correct so far.”

“Hmm…” Satoru didn’t seem too happy for some reason. “I assume you don’t know whether or not the building we’re heading for still exists?”

“There is no information about it in the archives, so I cannot say for certain. However, the chances that at least part of the building remains is estimated to be over fifty percent.”

“Really? Why do you say that? It’s over a thousand years old by now,” Satoru said excitedly.

I finally figured out what he was worrying about.

“We are currently headed toward Central Government Building No. 8, which is built from ultra long-lasting concrete. The concrete is a glycol ether and amino alcohol derivative admixture bonded with a polymer surfactant. The surface is vitrified…”

“You don’t need to go into detail. What you’re saying is that it’s not unusual for the material to survive a thousand years?”

“Theoretically, that is correct,” the fake false minoshiro replied.

“So why haven’t most other buildings survived?”

“The normal concrete used by the ancient civilization only lasts fifty years on average, and a hundred years at most. Shoddy construction, concrete mixtures with too much water, and mixtures containing sea sand causing alkali-silica reactions all shorten the lifespan of concrete. A third of the buildings in Tokyo were destroyed in the Nine-Day War, and most of the ones that remained fell apart within a hundred years. Weathered by acid rain, the limestone dissolved and flowed into large underground spaces, creating limestone caves in mere centuries that would have taken tens of thousands under normal circumstances.”

“What’s the Nine-Day War?” I asked.

“After normal people stopped hunting PK users, the PK users launched a counterattack. A group of less than a hundred PK users rounded up eleven million people, and over the course of nine days…”

“That’s enough,” I said.

I couldn’t bear to listen to what it was going to say.

Although it was never taught in school, I was well aware that human history was full of war and slaughter. But I didn’t want to believe that past cantus users, people no different from us, could kill those who were powerless.

Still, the psychobuster hadn’t been able to change the tide of war. I thought it was ironic that we, the victors of the previous war, now had to rely on the very device that had been designed to kill us.

Speaking of irony, Tokyo was another prime example. It’s concrete-clad facade had been created to block out nature, yet after the concrete had been broken down, it transformed into karst formations that had been around since the beginning of time. While Tokyo was a barren wasteland on the surface, it was a humid dungeon filled with nasty creatures below.

Kiroumaru suddenly stopped. He raised his snout and sniffed carefully. Soon, he located a thin crack in the wall and stuck his nose into it.

“What’s wrong?” Inui asked.

“Our pursuers. Their odor is coming this way. …fufu. I see how it is.”

“Hey, we need to get out of here fast…!” Satoru shouted.

“It’s alright. The enemy is still far away. Moreover, they’re in a different tunnel. Only their smell is being carried through on the wind, but it’s enough for me to roughly discern their formation.”

“Formation? You mean like how many there are?”

I was amazed by Kiroumaru’s skill.

“Yes. There are…seven in all. Fewer than I expected, but perhaps that makes them more mobile down here. Five of them I have never smelled before. They’re most likely rank and file. The other two I know well. One is the fiend. The other is Yakomaru.”

“Yakomaru?” Satoru yelped in surprise. “The general is coming after us himself? He’s been hiding until now.”

“There’s nothing surprising about it,” Kiroumaru smirked. “They need the fiend in order to stand a battle against you three. Furthermore, the fiend is their trump card–losing him would spell defeat. Taking personal command is the only logical decision if he is to ensure success.”

He spoke as if he would have done the same in this situation.

“Wait a minute. Do you think they know our number as well?” Inui asked sharply.

“It’s possible,” Kiroumaru said matter-of-factly. “There are dozens upon dozens of tunnels of all sizes under Tokyo and various air currents running through them. Even the air here is being carried away by the wind. Anyone who smells it will know how many are in our group.

Since we knew each others’ whereabouts, it might seem like we were evenly matched. But with greater numbers and the fiend as a trump card, they had an overwhelming advantage.

That’s what I thought at the time.

We continued quietly through the cave.

Since all the navigating was left to Kiroumaru and the fake false minoshiro, I had a lot of time to think.

Since the day before yesterday, the night of the Summer Festival, we had been plagued by one horrifying event after another. Because of that, I hadn’t had time to calm down and think about one crucial question.

“Hey, Satoru. Why did Maria’s kid turn into a fiend?”

He didn’t answer for a moment.

“…I don’t know. I haven’t the faintest idea how he was brought up. They use drugs, don’t they?” Satoru glanced quickly at Kiroumaru.

“But can that turn an ordinary kid into a fiend so easily?”

“In all the fiends that have been documented, they say the change occurs suddenly. Even if the parents are normal, the child can still be born with the makings of a fiend.”

“But does that really happen? Isn’t the probability incredibly small?”

Satoru shook his head. “There’s no point thinking about that now. In any case, we have to stop the fiend, or else our district will be destroyed. For that, we need the psychobuster.”

“Yeah, but…” I tried to put the hazy thoughts in my mind into words. “I can’t help but feel that he isn’t a fiend.”

“What are you talking about? You saw what he did. How many people do you think he killed all by himself? He even killed Shisei!” he raised his voice angrily.

Perhaps disturbed by his voice, something on the ceiling fell and plopped right onto Satoru.

“Uwa!”

Satoru’s surprised and pained yell echoed throughout the cave. He fell back onto the ground.

“Remove it quickly!” Kiroumaru said urgently, turning around.

I cast the lantern light over Satoru. There was a slimy creature thirty centimeters long stuck to his left shoulder.

“Don’t try to pull it off. Set fire to it and it will leave on its own.”

I began heating up the creature’s body. It would have been faster to set it completely on fire, but then Satoru would be left with a severe burn.

Nothing happened for two or three seconds. Then the slimy thing started to bubble and smoke. It stretched out its body, and four antennae appeared at one end.

“It’s a slug…”

I couldn’t believe it. Did slugs actually attack people? I burned off the four antennae. The monster slug writhed in pain, stretching its body to sixty, seventy centimeters, then fell to the ground. I immediately incinerated it in a flash of blue flame. The slug let out a squealing sound and disappeared in a puff of smoke and steam.

“Are you okay?” I asked.

“Please be careful! There are more above.” Kiroumaru pointed at the dark ceiling.

Inui lifted the lantern. There were tons of them hanging off the rock. It seemed like they had been about to follow the first slug and drop down on us, but the fire was making them sway back and forth in fear.

Inui tore them off the ceiling and flung them on the ground in a pile. There were probably over a hundred in all, squirming and waving their feelers in the air. Slime and bubbles spurted from them as they burned, and a chorus of screams rose in the air along with a foul smell.

I looked over at Satoru. His shirt near the shoulder was very slightly torn and turning red. Underneath, a large area of his skin was seeping blood.

“Does it hurt?”

Satoru nodded, teeth gritted.

“What the hell was that?” I snapped at the fake false minoshiro.

It stretched out a feeler, trying to see what I was talking about. Its movements were oddly similar to the slugs’.

“They are bloodsucker slugs. They cling to the cave ceiling and drop down on unsuspecting prey, latching on with barbed teeth and inflicting extensive skin damage before sucking their prey’s blood. If the prey is attacked by a large number of slugs, it will die from blood loss.”

“Aren’t slugs normally herbivores?” I asked as I disinfected Satoru’s wound with the first-aid kit in my knapsack.

“The usual slugs are of a different species, though the testacella genus from Europe are carnivorous and prey on worms. However, bloodsucker slugs are the only terrestrial gastropod mollusks that are known to suck blood.”

“Is it venomous?”

“It is most likely not venomous.”

I was slightly relieved to hear that.

“The wound may not appear grave, but the bleeding will become worse if left untreated. You should apply pressure to stop the bleeding,” Kiroumaru said, examining the wound.

“I had no idea such a nasty creature existed…it really is hell down here,” I muttered.

Kiroumaru shook his head. “This is just the beginning.”

We continued on, Satoru bearing his wound uncomplainingly. Due to the burn, we were unable to stop the bleeding. Even though the wound itself was shallow, I was still worried about there being venom. Not that I could have done anything about it, since I didn’t bring any antivenom. Later, I learned that the slugs’ suckers were so powerful that they could damage blood vessels deep inside the skin.

I had painkillers in the first-aid kit, but Satoru refused them because they might impair his ability to use cantus.

“This isn’t normal. None of this is…it shouldn’t be possible to live here for any length of time,” Satoru whispered.

“What do you mean?”

“Don’t you think it’s strange? That the slug evolved like that?”

“But…it’s sort of similar to what happens outside the Holy Barrier. The cantus that escapes through the filter of our consciousness is constantly leaking out and directed through the barrier…”

Even as I spoke I wondered where I had heard such a thing.

“Leaking cantus… That’s an interesting idea. But it’s true that all the new animals that have been discovered in the past millennium have been near the Holy Barrier.” He suddenly looked surprised. “It could be the cause of what’s happened here. People who live in Japan imagine Tokyo as a kind of hell. The cantus that leaked out when someone thought about Tokyo could have slowly changed it to become more and more hellish…”

A chill ran up my spine. Here we were, right in the pits of hell.

“Despite what the fake false minoshiro said, acid rain probably wasn’t the only element involved in the formation of these stalactite caves.”

A different thought suddenly surfaced in my mind.

Cantus leakage… No. That wasn’t my own thought.

It was as if there was some other person inside me.

Someone I know extremely well.

As we continued through the tunnel, Kiroumaru stopped abruptly and put his ear to the ground.

“What’s wrong?” Inui asked, startled.

Did he hear our pursuers’ footsteps?

“The rock here is thin. Underneath it is a deep pit. It’s a good place for a trap.