Mutual Benefit
"Wha-What...? Is this a quantum communication module? C-Commander!"
The moment Karen spotted the communication module in my hand, her eyes widened into circles as she cried out.
The ECHO, swept up in pure intellectual curiosity and ecstasy as an engineer, snatched the module from my hand like it was hers.
"......"
Her flushed face and ragged breathing were surprisingly stimulating.
"I-It’s not a model—it’s the real thing! How did something this precious end up in a rundown Ark like this?"
How?
It was all thanks to the Money Compass OOPArt.
The price to buy a communication module with the Money Compass was a mere 5,000 cash.
But I had to spend all of yesterday hunting zombies with the Arclight Squad to get that measly sum.
I was able to confirm once again that the area around the Ark is safe, but...
Considering I had to fight personally to earn cash, it wasn't the best setup.
Can't go on distant expeditions outside yet, either.
The Ark wasn't ready for that.
Hiding my complicated feelings, I asked Karen.
"Anyway, according to the Wanderer, we can make a synchronization device with this... Will that be possible for you?"
At my question, Karen carefully examined the module, turning it this way and that.
"This module alone isn't enough. We'd need memory alloy stronger than titanium-grade, a high-output arc battery, stable metamorphic silicon, stuff like that. With those... I think we could make it."
"Didn’t the girls from Arclight have scavenged a decent stock of materials from outside already?"
"That’s not nearly enough. Especially arc batteries—they're only extractable from combat ECHOs or military gear..."
The moment she finished, I used the Money Compass.
💰 Money Compass 💰
Arc Battery
Price: 1500 C
1,500 for a box.
Sounds dirt cheap, but I didn't have the cash to buy it.
Ah... I want to dump every last bit of money I had in my account into this.
If I could, the Ark's situation would be way different by now.
Anyway, once Karen finished, I immediately called the Arclight Squad together.
"Arc batteries, sir...?"
"Oh, Commander. Do you need arc batteries? For you, I'd discharge my core anytime... Want to have a little private chat, just us two?"
"...Pomen, the Commander doesn't like crude jokes like that."
"Hmm, you think so?"
Was this going on since the threesome with Alpha?
Noah had started checking Pomen in Arva's place more often.
Anyway, clutching my throbbing head, I looked at them.
"So, how do we procure those batteries?"
"Arc batteries are standard on military ECHOs and gear. Finding them won't be hard, but intact ones? There are no guarantees."
"The gear hasn't been wrecked for that long. Plenty should still be good."
Everyone nodded at Karen's follow-up.
Surprisingly, the main force of Ark 69 getting smashed by the Crawler Queen was an event that happened less than a month ago.
As I contemplated, Arva suddenly asked me carefully but firmly.
"Commander, if it's not rude... may I ask you something?"
"Go on."
"We're deeply grateful to you for risking danger to gather materials like the quantum module for our growth... but wouldn't it be better to prioritize facilities for your convenience over our upgrades?"
"...Huh?"
"Like... entertainment facilities to relieve your stress. Or defensive installations to protect the Ark."
I was speechless at Arva's words for a moment.
Her eyes brimmed with genuine concern and loyalty toward me.
It touched me so deeply that I couldn't help but chuckle out loud.
"Thanks, Arva."
I lightly patted her shoulder and continued.
"I get how you feel. But right now, making you all stronger comes first. That's how I—and this Ark— can stay safer."
"Understood, Commander."
"Yesss—! Commander!"
At my words, Arva and the other ECHOs flushed with joy.
"So, our target is the Hongwei-7 this time."
"...Where the 69 Ark main force's military gear lies scattered after total annihilation. But how much do we need, Commander?"
"Karen?"
"At least five boxes' worth."
"...That's a lot."
Arva nodded at Karen's estimate, tension showing on the squad leader's face.
To get that many, we'd have to camp outside. If there was a silver lining...
"Arc batteries are buyable as artifacts. No need to overdo it. Stay as safe as possible, but we do need to be swift about it."
"...Yes, sir."
The ECHOs' expressions eased at my words.
"Whew. Lucky our Commander's the type who can handle artifacts. Hey, hands off for a sec—!"
Pomen, trying to sneak in some skinship during the moment, got blocked by Noah's ironclad defense.
Honestly, I was getting a little hopeful, but no dice.
◇◇◇◆◇◇◇
We headed back to Hongwei-7 once more.
Under the ashen sky, a desolate world was shrouded in eerie silence.
We stepped once more into that place, where the scars left by the previous bloody battle had not yet faded.
"All units, maintain alert. Noah front, Pomen cover rear."
"Yes, Commander."
The ECHOs moved in perfect sync at my orders.
Our goal was clear— get the materials Karen needed to make the sync device.
To that end, we scoured the ruins of crumpled buildings and twisted vehicles.
Kiiiiiigggg!
"Damn, that's loud. Arva, be a bit gentler, will you?"
"Shall I put this blade in your hand, Pomen?"
"Sorry."
No work ECHOs, so we had to rip the armored vehicle panels by force.
And sliced massive truck frames with Arva's blade.
Each time, the noise drew zombies, sparking fights one after another.
Bang! Bang! Bang!
I smashed the charging zombies' heads with White Tiger nonstop.
Splat!
A runner on all fours ate White Tiger's rounds and sprawled across the ground, unmoving.
Was I hallucinating or what?
Even though Karen only touched it for a moment, I felt like the White Tiger's penetration power had increased.
"Arva, progress?"
"Almost done. About 15 minutes left."
"...Good work."
For the record, Arva handled detaching the arc batteries.
It was a waste of her top combat skills, no doubt.
But only her special blade could manage the work.
"I'll check the intersection. You cover elsewhere."
"Uh... all alone, Commander?"
Noah eyed me worriedly.
But our positions were within a distance that could be confirmed with the naked eye. Moreover, the number of zombies approaching the noise was no longer that many.
"Don't worry. I'll radio immediately if I sense trouble."
I reassured them and headed to the intersection building alone.
From a window, I waved to Pomen and Noah, signaling position.
"Sigh."
In a situation where we were short-staffed, this was the best option. And...
Bang! Bang!
A prowling runner's head exploded instantly, its body collapsing.
⚙ SYSTEM NOTIFICATION ⚙
Acquired 300C.
Acquisition History: Hongwei-7 Zombie Elimination (Combat Participation Reward)
Fighting solo let me pocket all the cash.
"Chump change. This won't even cover the ammo production cost."
Of course, it was pennies at most.
But pennies make mountains eventually.
"How much ammo is even left in the Ark?"
With only Pomen as the sole firepower-type ECHO, there was plenty. For now.
However, if the number of Echos increases in the future, it was obvious that the ammunition stockpiled in the Ark wouldn't last more than a few days.
"Need ammo factories too... Sigh. Mountains of work left."
How'd the previous guys survive?
If I could talk, I'd grab the last Fleet Commander by the collar and ask.
[Commander, you okay?]
"Yeah, no issues here."
[Commander, I think we’re good to go now.]
"Roger. Let's shift spots."
It was while I was standing guard and escorting Arva as she worked.
After a few moves, I took position on a 6th-floor rooftop.
While I was scanning the surroundings to make sure no zombies were coming our way...
[Po... Po-po...]
How long was I on watch?
Suddenly, a sound from behind made my heart drop to my ass.
"......"
I swallowed dryly, stiff neck creaking as it turned slowly as I looked at my back.
How long had it been there?
The Hachishakusama in white burial clothes crouched, staring.
Our eyes met; she approached silently, offering a familiar note.
[You were satisfied, right? If you don't hurt me and listen well, I'll satisfy you again next time. You don't have anyone to suck essence from here anyway, right? So let's help each other out.]
A few weeks ago.
It was the note I'd scribbled, desperately escaping her lair to survive.
She'd kept it like a treasured memento; it was pristine.
Then Pomen's voice crackled over the radio.
[Commander—? Can't see you. Where'd you go?]
I glanced at the Hachishakusama, stood up casually, and waved to Pomen.
Then, as calmly as possible,
"Still on the roof. No zombies in sight."
[I know, right? Did they all run away?]
Pomen waved both arms in the distance.
"Likely. This spot's a bit off from Hongwei-7 Command HQ. Arva, how much time left?"
[Sorry, Commander. Another hour at least.]
"No rush. Safety first. Everyone, stay sharp."
[Yes, Commander.]
I cut the comm after reassuring them.
Then I turned to the Hachishakusama behind me. Her blatant gaze pierced my skin.
What she wanted was obvious: my essence.
"Mm... See my crew? Time's short, so bear with it."
I soothed her, unbuckling my belt.
After a day fighting and running, I figured it stank—but she twitched the instant I pulled it out.
[Po... Po, po...]
The strange noises leaking from her mouth became rougher than before.
Lips peeking through jet-black hair trembled faintly. I jaw-pointed before me.
[Po—!]
Then, as if she had been waiting for that exact gesture, a giant shadow lunged greedily.
Her face amid raven hair held unearthly beauty.
That blood-red, elongated tongue wrapped, licked, sucked mine—then down to my balls.
"Hoo!?"
Cold, slick sensation dizzyingly spread.
Long time since last? Her essence-draining was blatant, relentless.
"Ahh."
Each time her tongue grazed my balls softly, spine-tingling pleasure escaped as rough breaths.
I felt it before, but seriously...
Her breathless vacuum fellatio was indescribably mind-blowing.