Just like Tsunade had said, for Ryuji, this was practically an impossible task — but for her, it was no more difficult than a casual stroll behind the house.
The most outrageous part was… she did it so effortlessly.
With a single leap, she could cover seven or eight meters horizontally and soar five or six meters into the air. If she exerted herself a little, she could even jump straight from the bottom of a deep canyon to the rooftop of a building — leaving Ryuji completely dumbfounded.
Sure, he knew Tsunade was a ninja. He'd seen what ninjas were capable of in anime. But witnessing it in real life was a completely different level of absurdity and awe.
Honestly, if Tsunade hadn't personally mentioned that she could still get cut by blades and wasn't especially resistant to piercing attacks, Ryuji would've thought she was practically a female Superman with an indestructible body.
The scenes he'd seen in anime were nothing compared to experiencing them in person. They were worlds apart.
Ryuji was certain — if it weren't for her fear of blood, Tsunade wouldn't have to worry about zombie hordes at all. Even standing alone on an open plain, she'd be perfectly safe.
Finally, after four or five failed attempts that afternoon, they managed to build a relatively safe shelter.
"Huh… the rules of this world really are strange. But I guess this is the best we can do for now."
Looking at the five-by-five-meter metal cube in front of them, Tsunade shrugged helplessly. After countless experiments, careful planning, and various tests to ensure that their activities inside wouldn't cause it to collapse, this was the final design they settled on.
This "house" didn't even have a conventional door. Their plan was to seal the entrance with two steel plates and then lock them down with system-generated blocks.
Around the walls, they had also designed shooting and ventilation windows, crafted from reshaped steel frames, so that Ryuji and Kiri could keep clearing out nearby zombies.
These openings, too, would eventually be sealed shut with real-world steel blocks — that was the only way to guarantee true safety.
"Even though I still think you're a bit too paranoid about these zombies… I gotta admit, this thing looks pretty impressive."
Kiri nodded approvingly at the house floating between the canyon walls.
"But still… it feels kinda sketchy."
She pointed at the gap between the support pillars and the so-called 'invincible walls.'
"We've tested it a lot, sure… but it just feels like it could fall at any moment."
"As long as we don't go adding blocks randomly or let the steel plates get pierced, it should hold. Besides, we've got a backup plan, don't we?"
Ryuji gestured to the undisturbed soil beneath their feet. Tsunade was currently using her fists to hammer steel plates into the dirt, reinforcing the underground tunnel and secret chamber they'd dug earlier.
If their shelter was ever truly overrun, they could retreat through this hidden passageway straight into a lower-level safe zone.
The reason they didn't go all-in on this underground plan from the start was simple — they didn't have enough steel. Ryuji worried that if they used all their resources to fortify an underground bunker, the endless zombie horde might eventually tunnel through the foundation, causing the whole structure to collapse in an instant.
Better to prepare for both possibilities.
During this time, Kiri had also tried to repair the cement mixer — only to shrug in defeat, admitting she'd bragged too soon.
Turns out… there wasn't even a motor inside. No amount of skill could fix that.
"Well, then… guess it's time to start setting traps."
Ryuji looked out over the vast, cratered expanse of land, took a deep breath, and pulled out a huge pile of gunpowder.
He started by fixing some wooden planks into the ground, then manifested empty cans, filled them with nails, packed gunpowder into both the cans and the planks, and grouped them together.
But the real insanity came next — he spread nearly half a meter of gunpowder over a wide swath of ground, then covered it with wooden floorboards. His plan was simple: if he couldn't make it explode, at least the entire floor would ignite instantly.
While working, he also kept crafting wooden spike traps from his inventory — caltrop-like barricades made of sharpened stakes — and set them up in layers across the center of the canyon, forming one defensive line after another.
"This guy… I think he's got a touch of paranoia…"
Kiri twitched as she watched Ryuji work. She genuinely felt he was going a bit overboard.
"Let him be," Tsunade said casually, laying steel plates and dividers over their escape route underground. "We've just about mined everything useful here anyway. We won't be staying long."
She didn't think much of the zombies' threat level either.
Time passed quickly while Ryuji obsessively set traps. After lunch, he crafted wooden planks to make three beds and some partitions inside their steel house, creating sleeping spaces for the three of them. He also filled two barrels with water and moved all their supplies next to the shelter.
At Ryuji's request, Tsunade and Kiri also helped set up additional defenses and scatter flammable materials — stuff Kiri could easily ignite from above with a gunshot.
The finishing touch? While the two women were cooking, Ryuji insanely dug out the only path leading to the outside world, completely cutting them off from potential zombie intrusion.
After all, they had system blocks. They could build their own path out whenever they needed.
Tsunade and Kiri just rolled their eyes at his paranoia and went off to shower. Afterward, they used the money Ryuji had given them to buy a ton of food and beer, preparing for a small feast.
Ryuji didn't care. He kept laying down gunpowder until nightfall before finally returning to their steel shelter, walking across the floating blocks, to have dinner with Tsunade and Kiri.
Lying on his soft bed, gazing at the starry sky through the window, Ryuji felt an overwhelming sense of peace. Even though beneath them lay a thirty-meter-deep abyss, he'd never felt so content.
"One more day tomorrow… maybe I can look for a quest at the police station or something. In America, police stations should have heavy firepower, right? Plus, I could probably improve that underground emergency shelter some more…"
Clutching his hopes for the future, Ryuji drifted off into sleep.
And then — just as the clock struck midnight —
A sandstorm began to blow outside.