How to Water a Cactus
"I'm sorry. I judged it more appropriate that I handle negotiations with the survivors myself, rather than leave them to you, Sera."
On the way back after the trade was done, Jin offered that apology in his familiar mechanical voice — and only then did Sera finally come back to herself.
"I am built with a fit and breathability that prioritize the wearer's comfort as much as possible, but I am fundamentally a closed structure. Being rendered unable to speak can trigger an instinctive fear response."
"Ah — no! That wasn't why I didn't say anything! I was absolutely not angry about your taking the initiative, and I was not frightened — not in the slightest!"
Jin's concern had been the product of careful thought about the friction that arises when an AI trespasses into human territory. Selfishness, greed, the terror of losing control over a situation you cannot command — those things lived in everyone.
But the reason Sera had been unable to get a proper grip on herself all day had nothing to do with any of that.
"Is it because the damage to the Residence Sector was worse than expected? Even so, they are only one group of survivors. There is a high probability that other groups remain under military protection."
"Ah — no! It, it isn't that either, it's just…!"
The situation was more grim than anticipated — that much was true. But when had that ever been a one- or two-day problem? The mere fact that she could still worry about tomorrow was something to thank God for on her knees. Compared to gasping for life in an airlock with not a scrap of oxygen left, or the life-or-death escape from the bridge, this was nothing.
"Then what is the problem? Your pulse is over one hundred twenty beats per minute."
"I — I have a request!"
"Yes?"
"When I'm inside the unit… c-could you, just a little, hold back your voice?"
The confession came out in a volume so thin her vocal cords had nearly stopped trembling. Silence settled for a moment. Before she knew it, Sera's shoulders had drawn in so tightly that the flush had climbed all the way to her earlobes.
At first she hadn't understood. She never imagined the difference between a mechanical tone and a human voice could press in so hard inside a cramped cockpit.
Every time that low, thick voice — indifferent on the surface, yet firm underneath — brushed her ear, her eardrums itched until she thought she would lose her mind.
Something has clearly gone wrong with my head. It might be orbital anomaly syndrome. Nothing else would explain this…!
The calm he kept even while the survivors they had finally found bristled with hostility and suspicion. The way he refused to be pushed around, instead remaining polite, holding his authority, and extracting exactly what he wanted. The occasional flashes of something almost human, even knowing he was an AI — all of it left her tangled in a confusion of feeling.
She had to be ready to climb into the suit and fight at any moment. She could not afford to stay in this undignified state.
"If I keep listening to your voice, Jin… my head gets hotter and hotter."
"…"
"I'm not good with words, but… you'll understand, won't you?"
How anyone was supposed to understand a sentence with both ends cut off, she had no idea. But she felt so thoroughly broken that a coherent explanation was simply impossible. Having wrung out every last scrap of courage she possessed, Sera squeezed her eyes shut.
A moment later, a soft tap-tap sounded — as if something had lightly flicked the head of the microphone.
"Jin?"
"Hoo—."
At the playful puff of air against her ear, she let out a mortified shriek she was certain she had never produced in her entire life.
Nothing would change.
She had said as much — and yet, only a few days after first meeting the survivors, Sera's attitude toward me had shifted dramatically.
She wouldn't let me watch her change clothes, and she seemed to be avoiding sleeping in the suit as well. The turning point had been hearing my real voice.
As someone who wanted to raise the Sync Rate, I was full of quiet regret — but I could hardly ask her to cling closer. An artificial intelligence craving affection from a human was a contradiction in itself.
And there was a bigger problem besides.
"Haa… it looks like things are more or less cleaned up."
Sera discarded a plasma sword that had reached the end of its life and wiped the sweat from her brow. The third floor of CSJ Company headquarters. True to her insistence that one should never rely solely on the suit's performance, she had single-handedly destroyed the active security systems and guard robots.
Two hours of forced standby a day, six hours of sleep, then movement, securing supplies, clearing the company's internal guard robots and variants — there was no rest in these busy days. Whenever Sera spent long stretches out of the suit, I was nothing more than a motionless lump of scrap iron.
Even so, once that stifling wait ended, there had always been a reward for the patience — something I had privately looked forward to.
Until now.
"The floor above this is probably the control room, but I'm running out of strength. After the next trade, I'll have to climb up in the suit."
"Well done, Sera."
Even non-lethal rounds hurt considerably when they hit, and bruises mottled her skin here and there. When I carefully reached out with a chilled mechanical arm to rub the injured spots, she flinched away again.
"Ah — I'm fine. It doesn't hurt much."
Lately she was always like this. She washed before climbing into the suit. Even when she yawned, she wiped the corners of her own eyes. She still couldn't swallow the liquid rations in one go and would spit them back out — but she always cupped them carefully in both hands so nothing dripped onto the unit. That was a relief for me as well, since I had to reabsorb the mess, but the rest of it was not.
Power's running low.
Speaking, moving, hauling supplies for the survivors — everything required power. And if the inflow from my only supply source cut off, the situation would turn critical. Right now I was drying out like a single cactus rooted in the desert.
"Wounds need to be treated in time."
"As you know, Jin, I'm sturdy. Injuries like this heal in a few hours."
"I am acting for Sera's survival—"
"And what exactly does wiping my sweat have to do with that?"
"——."
Maybe it was the impatience. A small beep slipped out before I could stop it, and the moment I realized it, Sera's eyes grew steadily sharper.
"Come to think of it, you're an AI, Jin — and yet you're unusually fixated on my body."
"I am not fixated on Sera. I am simply keeping the body clean."
"Hmm. Really?"
With a look that suggested she had decided something — different from her usual self — she abruptly opened her mouth and raised a finger. Between neat rows of teeth, a small, pink, almost adorable tongue emerged, and she brushed it lightly over the tip of her finger as if dabbing a stamp pad with ink. The way she held it out toward the mechanical arm looked like something she had done a few times before.
"Something like this would rinse clean with water, wouldn't it? Unless, of course, you specifically want my saliva, Jin."
Sticky saliva gleaming on a fingertip that had never known nail polish or hand cream. Combined with the scent of skin rising from her palm, the sweet fragrance was like a cookie pulled from a jar of honey. It sounded perverted to put it this way, but her saliva was not the kind of thing one could casually sample. Unlike blood from a wound or sweat from the pores, you had to open a mouth and take it directly. The only times I got any were when she spat out that miserable liquid ration, or a few drops mixed into the water that spilled when she drank.
— Shuuuk!
"…I knew it."
Before I could stop myself, the mechanical arm with the intake port sucked her saliva clean, and Sera murmured under her breath. With no room left for excuses, I had no choice but to carefully tell her the truth.
"What's going on? Can you lie, Jin?"
"No. That I am not fixated on Sera was not a lie."
"Then what about just now?"
"…A certain portion of the energy required for my operation is obtained from Sera."
"What? Don't you run on a plutonium cell?"
The puzzled tilt of her head was only natural. Even I, with zero scientific knowledge, knew the law of conservation of energy. The idea that this massive steel suit moved on a few drops of sweat was pure nonsense. She had seen so many strange functions surface by now, and she believed I did not lie — so the reaction stopped at mere doubt.
"There is no recorded information regarding the power source, but it is certain that Sera's assistance is required."
"Auum…"
Hearing my explanation, she let out a faintly complicated sound. Embarrassment, incredulity, and — unexpectedly — a small thread of pleasure mixed across her face in a colorful expression.
"Is that true?"
"As far as I am able to explain, yes."
"It's true that on the bridge… and afterward, every time I slept…"
That had been the part I feared most, so I was relieved she didn't wrinkle her face in disgust. Of course, that was only because she still believed I wasn't human. No one gets offended when a washing machine cleans dirty clothes or a hair dryer dries their hair. Which was exactly why this one thing could never be discovered.
I was bowing my head like a criminal awaiting a judge's sentence when Sera asked:
"How much of my bodily fluids do you need?"
"Insufficient data."
"Is wiping sweat or tears more efficient than drawing about a liter of blood?"
"Insufficient data."
"What do you even know about yourself, Jin…"
If she was the type who prioritized efficiency, she really might draw a full liter of her own blood. If that filled my power reserves in a rush, it would be genuinely terrifying.
"How much time is left until the next rendezvous?"
"Eighteen hours."
I delivered the mechanical answer while nursing a false sense of hunger — and then weight suddenly settled against me. Sera had leaned back into the seat.
"For now, I understand. It's hard to accept by my common sense, but you are special, Jin."
"Thank you."
"If we gather data, we'll figure out the rest eventually."
The words came while I was absorbing energy like rain in a drought from the slightly damp hair at the nape of her neck where it touched the inner lining. Gather data? The front of the suit was fully open, so I couldn't see the expression of Sera, who was facing forward. When the mechanical arm with the camera approached, she caught it in her hand and pushed it down.
"We've stocked the supplies, cleaned out the base, and we still have time."
"Sera?"
"So… shall we try a little experiment?"
Her gaze stayed fixed on the wrecked guard robots and the third-floor corridor. But the back of her head was tapping lightly, insistently, against the interior of the suit.