After Morgan of Proper Human History withdrew, the group rested at their camp beside the cornfield until late into the night. Then the Storm Border flew in and joined them.
Romani, Da Vinci, and Sion found Tepeu quite fascinating, and soon struck up a friendly exchange filled with curiosity and academic enthusiasm.
At the same time, the Storm Border crew began harvesting corn, making it one of their main sources of fresh food during their stay in this Lostbelt.
They also used the cornfield area as the foundation for a temporary headquarters to launch their assault on the First Netherworld, the waters of Tlatlauqui.
After all, although Chaldea could not directly cross the boundary of the First Netherworld and descend deeper into Mictlan, the 'Alien God' and the final Crypter, Daybit, could appear at any time during this period.
As usual, most of Chaldea's personnel remained at the main base. Only a few individuals, including Aesc and Shiomi, followed the river upstream toward the First Netherworld, the waters of Tlatlauqui.
Since Morgan had said she would be waiting for Chaldea there, they did not intend to keep Proper Human History's Morgan waiting for long.
They still needed to reclaim an important authority.
For them, that was the most urgent matter.
"It's definitely a vast stretch of water. You can't see the end of it," Scáthach said, raising her head to look toward the upper side of Mictlan's ring-shaped land. "But it doesn't look like a normal river or a lake."
If one flew along the surface, it would take at least two hours to reach the point directly above.
Not only that, but when walking along the surface, every area along the inner side of the ring had identical gravitational perception.
This was the second phenomenon discovered yesterday by Team A during their survey expeditions in both directions.
Just like on any landmass on Earth, there was no sense of falling.
The preliminary conclusion was that when this underground world was formed, an existence known as Maia had determined the physical laws of this world.
"That's not the point," Aesc said as she looked out across the waters of the First Netherworld. "This so-called First Netherworld has already been completely turned into a Magical Workshop."
"Indeed." Shiomi crouched by the shoreline, observing the water's surface. "It doesn't seem to reject anyone entering. But whether you can come back out safely afterward is another matter."
"It's practically an invisible fortress," Skadi commented. "Its strength rivals the barrier I used to maintain the Norse world and resist Surtr's flames."
Scáthach thought for a moment.
"The enemy holds the terrain advantage. Rushing in would be unwise..."
"Who said anything about rushing in?" Aesc replied.
She took out a sword.
Artoria's Holy Sword of the Planet.
After the Storm Border's Holy Sword Concept Armament was completed, the Holy Sword now served mainly as the core that enhanced the weapon's power during activation. It did not matter even if it was taken away from the Storm Border.
After all, the conceptual armament created by fully analyzing the Holy Sword, 'Hume Barrel · Ray Proof', had reached a level of completion even higher than Sion had expected.
Setting aside specifications, its completion was on par with the shadow of the Holy Lance, Add.
"I see."
Shiomi and the others, including his master, immediately understood.
"It may look like the entire First Netherworld has been turned into a workshop, making its location uncertain. But precisely because its coverage is so vast, the workshop exists like an island in the Wandering Sea. It can be said to exist everywhere within this First Netherworld."
Aesc's fairy eyes glowed with a deep blue light as she already saw through the defensive structure that supported the First Netherworld's inherited barrier.
And the Holy Sword of the Planet, the Noble Phantasm wielded by King Arthur, the mortal enemy of Morgan from Proper Human History, was the perfect tool to shatter that inherited defense, forcing the opponent to reveal their coordinates and fixing their position.
She had no time to enter and wander through a pointless labyrinth.
There was no reason to waste time.
The longer things dragged on, the greater the chance of something going wrong.
If the 'Alien God' appeared at any moment, it would bring nothing but trouble for Chaldea.
"Then..."
Shiomi stood behind Aesc, while Scáthach and Skadi took positions on either side of her.
The three of them simultaneously activated Rune Magecraft, amplifying Aesc's magical energy. This allowed her to reduce the original cost while pushing the borrowed Noble Phantasm to 200% output.
She had already used this Holy Sword more than once. As a fairy who once bore the mission of forging the Holy Sword, her affinity with it was nearly on par with its current wielder.
"Looks like they noticed."
Aesc showed a faint smile.
The inherited defenses of the First Netherworld suddenly began to strengthen. It was an obvious response to sensing the Holy Sword's mana.
But it was already too late.
Altering a formation of this scale required time, even for the most exceptional Magus.
Even the few seconds that would seem impossibly fast to an ordinary Magus were, to someone of the same level, a fatal opening.
"Breath of the stars, gather here. Strip away the false trappings and reveal the true form of the First Netherworld to me!"
Aesc raised the Holy Sword high. The golden mana coiling around the blade surged upward as if it would pierce the sky.
"[Excalibur]!"
The massive golden blade of mana fell forward, crashing down upon the waters of the First Netherworld and cleaving through waterfalls and raging currents.
Like the legendary moment when Moses parted the sea, the waters split open, exposing the damp, soft earth beneath.
Enormous waves surged upward on both sides, rising more than ten meters high, before rushing back toward the waterless center. Vast amounts of river water evaporated under the Holy Sword's power, and dense mist quickly filled the entire First Netherworld.
A few seconds later, a soft drizzle began to fall.
The water that had been swept into the sky returned to the waters of Tlatlauqui in the form of artificial rain.
Holding an empty umbrella formed from a projection of mana, Aesc stepped onto the still-restless surface and walked into the First Netherworld.
"So it's Arthur's Holy Sword. Your relationship must be quite extraordinary."
Morgan looked at Aesc. She was already soaked through. Water dripped from her hair, running down her body in thin streams.
Just protecting herself from being caught up in the destruction of her own formation had clearly taken considerable effort.
"It's nothing special. After all, we're practically family now."
Aesc stopped walking and looked across the deeply split waterfall channel toward Morgan on the opposite side.
"As his wife, borrowing a Noble Phantasm from my husband's knight isn't anything improper."
"Family?"
Morgan stood up.
"To tolerate Arthur sharing his possessions. You're even more dull than I imagined."
"My husband isn't some object."
Aesc tilted her head slightly, smiling at her.
"You treat men like tools and only know how to seize power and status. Of course you wouldn't understand."
She continued, her voice calm.
"I'm curious. The 'me' from Proper Human History... did you ever truly love anyone?"
"That kind of weakness is unnecessary for the 'True King' who inherits Britannia."
Morgan dismissed the idea with complete disdain.
"The 'True King' of Britannia, huh..."
Aesc stretched a hand beyond the edge of her umbrella, letting the rain fall into her palm.
"You used to be such a good big sister. But now you only call Artoria 'Arthur'."
"You really do talk too much!"