Four days until the gate opened.
Four days to prepare for an apocalypse.
The command tent was crowded with officers, each presenting their portion of the defensive preparations. King Alderon III sat at the head of the table, his Sword Saint standing just behind his right shoulder, her presence somehow both unobtrusive and impossible to ignore.
Lord Casimir gestured at the map spread before them. "The outer defensive line is complete, Your Majesty. We've erected battlements here, here, and here-" he indicated points on the map "- creating overlapping fields of fire for the archers. Pike formations will hold these positions, with sword and shield reserves positioned to plug any breaches."
An engineering officer stepped forward. "The spike fields are nearly finished, sire. We've covered the entire approach from the gate with caltrops, barbed barriers, and pitch trenches that can be lit on command. Anything coming through will have to navigate a killing ground before reaching our lines."
"The mages?" the king asked.
"Positioned in rotating shifts, Your Majesty," Vera reported, her sharp eyes moving from the map to the king's face. "We have offensive casters on the elevated platforms for maximum range, shield specialists integrated with the infantry formations, and detection mages monitoring the gate's magical signature around the clock."
"Supply lines are secured," another officer added. "We can maintain the current force for three months if necessary, longer with rationing."
The king nodded slowly, absorbing the information. His guard- the Sword Saint- leaned forward slightly, studying the map with the focus of a predator analyzing terrain.
"Casualties projections?" the king asked quietly.
Silence fell over the tent.
Lord Casimir cleared his throat. "Based on previous gates of this size... twenty to thirty percent in the first clear, Your Majesty. Possibly higher."
Six hundred to nine hundred soldiers. Dead or permanently disabled. In the first engagement alone.
The number sat heavy in the air.
King Alderon drummed his fingers on the table. "And the High Arch-mage Leon? I expected him to be present for this briefing."
The officers exchanged glances. Several faces showed expressions that were equal parts relief and something else- was that amusement?
"Your Majesty," Aldric spoke up, stepping forward with a slight bow. "High Mage Leon is... preparing."
"Preparing?"
"He has been sequestered in his tent since first laying eyes on the gate," Lord Casimir explained. "He seemed..." the lord paused, choosing his words carefully, "...displeased that creatures would dare invade our sacred land."
"There have been occasional magical flares," Tomás added, his quiet voice carrying in the tent. "Emanations of power from his tent. We believe they are the result of his, ah, temper."
The king's eyebrows rose. "Temper?"
"But that's not all, Your Majesty," Aldric continued quickly, seeing the concern on the king's face. "Despite his anger, the High Mage has been working tirelessly on our behalf. He's been improving magical formations- dozens of them. Modifying circles to cause maximum damage to the invaders."
"He's our ace in the hole," another mage declared with conviction. "Our chance to completely overturn the situation."
The Sword Saint shifted slightly, her expression neutral but her eyes sharp. The king noticed her reaction and waited for her assessment. She gave the barest shake of her head- not disagreement, just acknowledgment that she had no information to offer.
"His tent has been off limits without invitation," Aldric explained, noting the king's confusion. "We didn't want to disturb his work. But for you, Your Majesty, I'm certain he would make an exception if you wished to-"
"No," the king said firmly, raising a hand. "If the High Mage is in a state of volatile magic, he should be left alone to complete his preparations. We'll speak with him when he's ready to emerge."
Relieved nods around the tent. The last thing they needed was to anger the kingdom's most powerful mage right before a battle.
"Very well," King Alderon said, returning his attention to the map. "Continue with preparations. I want hourly reports on the gate's status. Dismissed."
Meanwhile,...
Leon had a piece of chalk balanced on his nose.
He was slouched in his chair, one leg hooked over the armrest, a borrowed book titled Advanced Aerial Dynamics in Combat Spellwork held in one hand. His other hand tapped a rhythm against his thigh- the beat from a J-pop song that had been stuck in his head since this morning.
"Kimi no namae wa- " he hummed tunelessly, eyes scanning the page.
The chalk wobbled. Leon tilted his head slightly to compensate, not breaking his reading rhythm.
The problem was flying creatures.
He'd seen them through the gate- things with wings, things that glided on membranes, things that seemed to just float through the air with no visible means of support. The defensive formations he'd designed were great for ground-based threats. Walls of force, concentrated fire zones, synchronized bombardment patterns.
But flying monsters? That was a three-dimensional problem, and most of the magical formations in this world's arsenal treated combat as essentially two-dimensional.
The chalk fell off his nose. Leon caught it absently and started doodling on the slate beside him.
Traditional anti-air defenses back on Earth used tracking systems, predicted trajectories, calculated intercept vectors. Here, the mages just... pointed up and threw fireballs? That seemed inefficient.
What if he could create a formation that detected aerial movement and automatically calculated optimal firing solutions? Feed the data to multiple mages simultaneously, creating a coordinated defensive umbrella?
The problem was the detection component. He'd need something that could sense movement in three dimensions, track multiple targets, and update in real-time.
Leon sat up, the chair creaking, and started sketching rapidly. A spherical detection grid. Multiple anchor points. Each mage in the formation receiving targeting data through... through what? How did you transmit information magically?
He flipped through the book, humming the chorus now. "Zenzenzen zense- "
There. Communication matrices. Apparently mages could share information through linked circles, though it was usually used for coordination between allied forces, not tactical data distribution.
Leon started combining concepts. Detection sphere. Information network. Automated targeting calculation. If he could integrate all three...
A sudden thought made him pause. Would this work without him having magic? He'd need other mages to power it, obviously, but could he even create the initial framework?
Only one way to find out.
Leon stood, stretched until his spine cracked, and surveyed his tent. Every surface was covered in chalk diagrams. The floor, the walls, hanging slates, even a piece of canvas he'd commandeered and covered with geometric patterns.
His "temper tantrums" as people apparently called them.
Leon grinned. If they thought magic flares were him being angry, they should see him when he actually got frustrated. Back on Earth, a failed calculation meant swearing at his laptop and stress-eating convenience store onigiri. Here, apparently, it meant people assuming he was a wrathful arch-mage barely containing his power.
The misunderstanding was almost too perfect to correct.
He returned to his slate, balancing the chalk on his nose again out of habit, and continued working on the aerial defense problem.
Four days until the gate opened.
Four days to turn theoretical mathematics into something that might keep people alive.
The pop song continued in his head, a ridiculous soundtrack to the end of the world.