　The soul residing within the body. Gathering together, it propels the vast spacecraft. Even though I've heard it before, I still can't believe it. For the 'Souls Engine,' is the Soul Operator nothing more than a fuel tank, tirelessly pouring energy into it? That question lingered in my mind like an unresolved knot.

　"Souls Operator 150, how can I assist you?"

　"Oh, yes. The communication passage connecting the interior of Economy Facility F has somehow been disrupted."

　"Do you have any idea of the cause?"

　"None. Could you first check if the cutoff mechanism is functioning properly?"

　"It seems an inspection is necessary. I will check it now."

　Feeling a bit annoyed, I still complied with the request, operating the control panel to thoroughly investigate the status of the cutoff mechanism.

　"No anomalies detected. No signs of damage either. While something might indeed be happening within Economy Facility F, it's beyond the jurisdiction of the Soul Operator unless it's a facility or energy supply-related issue."

　"I see. It's disappointing to hear it's beyond your jurisdiction."

　The Soul Operator acts as a kind of doctor for the 'Souls Engine.' They repair facilities and restore energy. However, they are not omnipotent.

　"I believe there are entities responsible for facility coordination or block leadership. It would be better to consult them. That's what I think."

　"Understood. I'll inquire with the facility supervisor."

　"Soul Operator 150, I will now terminate the communication link."

　"Thank you for your assistance."

　Thus, a brief silence fell upon the cockpit, a rare moment allowing us Soul Operators some rest.

　I turned away from the control panel, closed my eyes, and let the light and sound wash over me. But amidst the sensory input, I felt something leaving my body, originating from within.

　The cause was the line connecting us Soul Operators to the 'Souls Engine.' It was right there, easily visible, without the need for searching. However...

　"Soul Operator 150, it's you?"

　"Soul Operator 103 here. I have a request for you."

　"What is it?"

　"Instead of the faulty line, could you connect me to the backup line?"

　"Even after testing?"

　"Yes, that's fine by me."

　Responding to 103's matter-of-fact tone, I let out a deliberate sigh. Below the display, a small icon appeared. I pressed it firmly, simulating the activation of the backup connection. It was dull, lacking any excitement. Yet, understanding the process was enough, even if the test lacked excitement.

　"Is it done?"

　"If it's a test."

　I replied with a single word, observing 103's reaction. However, their tone remained emotionless, devoid of any discernible feelings.

　"If it's a test, then I've just finished it."

　"Then please execute the backup connection for me, and ensure its completion."

　"Very well, please wait a moment."

　With caution not to break the contact mode, I intentionally disconnected one of the faulty lines. Just one. If I could, I'd sever them all. That way, everyone would be liberated from the curse of the 'Souls Engine.'

　"Soul Operator 150, hostile reactions detected."

　"Huh? That's not..."

　"150, I don't want to hear anything further."

　"...Then, what should I do?"

　"Exactly as requested initially."

　103's flat response sent a shiver down my spine. There was no vitality emanating from them, clearly distinguishing them from others.

　However, there was something even more mysterious. Despite the complexity of the systems onboard, the Soul Operators were capable of handling most issues. Therefore, the request for a backup connection was unnecessary, recognized as an extraneous action aimed at efficiency.

　"If that's the case, let's resume from where we left off."

　But the question nagged at me. I doubted I would ever voice it. Most Soul Operators detested unnecessary actions, striving to eliminate waste. That was one of the few common traits among us.

　"How long will it take?"

　"Just a moment."

　While saying so, I operated the controls. Once you understood the process, it wasn't difficult. However, I myself, or rather, my soul, seemed to be having issues.

　"Soul Operator 150. Current soul level is below 10%."

　I was indeed the fuel tank. Sensing the dwindling soul within, I pondered. But I knew I had to keep burning the soul until the end. Perhaps this would be my final contact.

　"Reporting to 103. Backup connection completed."

　I awaited 103's response. I didn't anticipate any emotional response, just gratitude would suffice. Yet, 103 remained silent.

　"103?"

　No response. At that moment, I attempted to initiate a bio-reaction check, but the contact mode automatically terminated, preventing me from doing so. It seemed that during the contact, 103's soul had burned out, resulting in an invalid reaction.

　But 103, I felt, had found the answer I sought. Liberation from the curse of the 'Souls Engine,' and the means to achieve it.

　"Soul Operator 150. Soul level has reached 0%."

　For me, that was the only answer, the only thing I believed, imprisoned within the 'Souls Engine.' But that wasn't the case. When the soul burns out and the body disappears, the role of the Soul Operator naturally ceases. The same goes for the backup connection. In the grand scheme of things, each individual action holds little significance.

　"Soul Operator 150's invalid reaction detected."

Reflecting on the moment of death, I found meaning. It was the only meaningful thing amidst all this.