Chapter 20
From The Start
They set up camp near the site of the attack.
The giant-bodied Diablo soldiers, along with the prince himself, stood frozen as they listened to Casca.
“Luminus once drove it away?”
“Just drove it away…” Casca said.
“No kingdom of men could ever hope to slay a monster the size of a fortress.”
“How did Luminus do it?”
“The method was…”
Her voice carried over the scene like a voice-over, as images showed Diablo sea-soldiers diving down into the depths—over a thousand meters beneath the isle.
We had to use the truth that waves travel faster through water than through air.
We would scatter “buoys” around Diablo Island, set in three rings of range: A, B, and C.
“Why three?”
“Because Leviathan cannot move through the ocean without producing waves. With a body that size, its movements are no different from a tsunami. The problem is your soldiers can’t detect them—they’re born too deep. Deep-water waves have such low vibration that they’re imperceptible.”
What Casca explained to them was essentially the natural science of wave propagation.
“You’re familiar with tsunamis, aren’t you?”
“They happen every year.”
“That beast is just like a tsunami. The shallower it gets, the larger the waves. The deeper, the smaller. But the speed of the wave born from Leviathan never changes. When one thing increases, the other must decrease.”
v = f λ
“These buoys can detect vibrations in deep water. I need your soldiers to deploy them. They’ll float on the surface, tethered to anchors on the seafloor.”
Freya was ordered to carry this out.
Together with her unit, she hauled the newly made buoys out to sea. The jellyfish-like Diablo soldiers dove along the thick ropes, fastening each buoy to an “anchor” at the seabed.
When even the slightest tremor occurred, the anchor—tuned to Leviathan’s natural frequency—would relay it up the rope to the buoy.
“It had better work,” Freya muttered with distaste before surfacing and leaving one in place.
“With the outermost ring, you’ll have about one hour’s warning,” Casca said.
“An hour? More than enough time for them to report to you.”
“And the other rings?”
“Confirmation.”
Casca had known from the moment she stepped foot here.
Diablo was an island, the sea winds always strong. The buoys could be shaken by mere wind, producing false alarms.
“But if all three rings shake at once,” she explained, “then it’s not the wind. The spacing between the rings ensures that wind loses force before reaching the next. The only thing that can make them all vibrate together is something rising from beneath the sea.”
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Fury understood the idea.
“How long have humans had this, Casca?”
“Long enough that tsunamis aren’t our problem anymore.”
Still, Casca wasn’t a scholar—she was a soldier. She only knew the principles. In her homeland, they could calculate distance and timing precisely, but here she offered the basics: if all three rings glowed, something was coming—whether tsunami or beast.
“And if your trinkets don’t work?” Freya sneered.
Casca’s answer was ready. She smiled slyly at her.
“Then extend my stay.”
“At that moment,” Dan said, setting down the apple, looking at the princess, “I felt like my eyes were opened. It was the point when I stopped underestimating humans completely.”
“You may be weaker, but I cannot belittle beings who understand such abstract concepts.”
Looking back, the very fact that humans could think like this was astonishing. And through the eyes of one not human, it was genius.
“This is the power of passing knowledge forward.”
And a few years later, Prince Fury himself decreed something monumental—the development of a written language of their own. The purpose was to pass things on.
“No wonder Lady Casca knew so well… Besides Diablo, only Luminus and Zentinel face tsunamis so often, Mr.Fury.”
Especially Zentinel. Tsunamis, earthquakes—they endured them constantly, and thus mastered them.
“It was only Mr.Fury who trusted me then. He even went to the king himself, asking for my stay to be extended.”
“You still got your benefit in the end. One way or another.”
“How long was it extended, Lady Casca?”
“Five months.”
She raised five fingers.
“Guess which mutt nearly died that day?”
“…Just one person, I’d wager.”
“Oh? Nearly died, huh?”
Zeedee Lamb appeared from behind, face haggard from nights without sleep in the lab.
“I’ve been listening long enough… That vile paladin painted me as some jealous witch in her story! Wretched!”
She lunged and grabbed Casca by the throat right before the prince, the two grappling until the table shook.
Dan plucked grapes idly while watching.
“Out of the cave yet, Freya?”
“Hardly! This is just temporary! I know when I’m gone you spend your time with her, Your Highness!”
“Wow, how’d you know? Amazing.”
“I’m your wife too!”
“Oh right, forgot. Mm-hm.”
“Why do you speak as if I’m lesser than her, Your Highness!?”
“That’s just it. My husband knows who the true wife is, and who’s the paper-wife. Hehe.”
“You—!!”
“Grapes, Lady Freya?” Nora offered.
“Thanks, little one.” Munch munch munch
“I’ll summon the guards and have you thrown out! This is an academy! Not a gorilla’s playground!”
Casca: “Sounds like someone’s asking for the seafood pot.”
Dan rolled his eyes. Nora leaned in.
“Mr.Fury… did you ever catch it?”
Four months later.
Casca still lingered on Diablo Island, overseeing the Leviathan detection buoys and living her life. She grew accustomed to the climate, the food, survival. And most of all… her closeness with Fury deepened.
How close?
Close enough that Casca brought out something called a “board game” and played it with Prince Fury on the hillside one afternoon.
“You’ve gotten good, Prince. You learn fast.”
She sat with one knee raised, leaning her weight to the side, golden eyes fixed on the handmade board pieces, twirling one between her fingers with a smirk.
“For a beginner like you, not bad.”
“Make up your mind—am I ‘Prince’ or just ‘Fury’? Choose, Casca.”
“I respect you… but sometimes your cheek makes me want to call you lizard.”
“Terrifying, General.”
“See? That.”
She puffed her cheeks.
“This is what humans play in the army?”
“We play many things, but this is most popular among high officers. A trial of wit and strategy.”
She said,
“Ever heard this saying, Fury? You can’t hide your true nature on a game board.”
“I can. I just lose on purpose. I’ve nothing to lose.”
“Hey! That’s no fun!”
“So you must be very skilled.”
“Not bad… Careful now.”
Casca slid her piece, taking one of Fury’s.
“You need much more practice, handsome.”
“Handsome?”
Fury tilted his head.
“What is that?”
“It means a man who looks good.”
“And what is ‘looks good’?”
“It means charming. Someone you’d want as a mate.”
“Shouldn’t you say that to your husband?”
“…I don’t have one.”
“You don’t?”
“Always work, work, work in the army. Surrounded by men. My standards are high.”
“Maybe that’s why you’ve none.”
“…Guess so.” Casca drooped.
“Truth is, I’m lonely too. Wish I had a partner… But here? No humans. Should I take a Diablo mate instead?”
“Not a good idea, General.”
Fury captured her piece.
“Different species. It won’t work.”
“Who said so? The old scriptures never forbade it.”
“Are you that desperate?”
“Want to apply?”
“Bold, inviting me.”
“Joking, jeez~”
“I might consider. I enjoy being with you. You’re the only one who understands me.”
“!?”
Casca froze, eyes wide.
She stared at him. Fury looked up.
“Casca? Your move.”
“…Ah…”
“What’s wrong?”
“Did you just say… you like me?”
“Did I?”
“…Forget it.”
She dropped her gaze to the board.
But then—
Casca’s eyes drifted far, out to sea. She stood suddenly, dropping the piece in her hand.
Fury turned to follow her gaze. And he saw—
The mana-crystals on the outermost buoy line glowed.
Red. Yellow. Green. All three rings.
