Over a thousand foreign tribe warriors had crossed the border river.
From what he could see, there were many from the oni tribe and the lizardmen tribe. There were also plenty who looked completely human in Rest's eyes.
"Foreign tribes using magic... That's not what I heard."
Rest frowned, a puzzled expression on his face as he watched the foreign tribes appear from empty space like a mirage.
He had heard that, in exchange for their powerful physiques, wings, shells, and scales, foreign tribes were not adept at magic.
"And yet... isn't that magic pretty high-level?"
They had been hiding... Was it an optical camouflage spell?
By twisting and shifting the light, they had probably made themselves impossible to see.
"You're telling me foreign tribes, who are supposed to be bad at magic, used such high-level magic...?"
Something was definitely wrong.
Rest felt a wave of suspicion, but still took aim at the monsters appearing at the border.
"[Fireball][Amplify][Compress][Accelerate]!"
"GYAAAAAAH!?"
A compressed fireball. He hurled it at the enemy army like a bomb, and a massive pillar of flame rose into the sky.
With a single spell, several foreign tribe members were blown away.
"Hmm, they're tough. And their morale is strangely high, too."
Unfazed by the explosion, the foreign tribe warriors charged forward.
The soldiers on the castle walls returned fire with magic and arrows, but their attacks toward the outside were weak, partly because they were distracted by the winged tribe above their heads.
Even as this happened, the foreign tribe soldiers were rapidly closing in on the castle walls.
"I see..." he muttered. "This is troublesome. An ambush much more thought-out than I expected."
The winged tribe launched a surprise attack from within the clouds.
Seizing the moment their attention was drawn, the main force, concealed by magic, attacked.
From our side, it was a double whammy. If Rest hadn't noticed, they might have fallen squarely into the enemy's trap.
"It'd be better to clear up the ones above first...!"
Rest thought for a moment, then constructed a spell.
"[Wind Sphere][Amplify][Compress]...!"
Just as he had once done with fireballs, he amplified and compressed the wind sphere. Then, he sealed it using barrier magic.
He repeated this several times, creating a single massive 'Wind Bomb'.
"I'm not using [Flame Progenitor God]... I promised, and besides, I'd risk catching my allies in the blast."
But... with wind, there should be no problem.
He had adjusted the power as well. He fired the 'Wind Bomb' toward the sky.
"Take this... [Wind Progenitor God]!"
Once the 'Wind Bomb' had risen to the height of the clouds, he canceled the barrier.
The mass of atmosphere sealed inside exploded.
A shockwave erupted, blasting away all the winged tribe members flying in the sky.
"Whoa...?!"
"What the hell was that wind just now?!"
A strong downdraft also swept over the fortress on the ground, but it was just a gust of wind.
There was no damage as severe as that suffered by the winged tribe who had been exposed to the shockwave at close range.
The winged tribe members who had been flying in the sky fell one after another and were slammed into the ground.
"Good... the ones above are taken care of now!"
Now we can focus on the enemies outside.
They've gotten closer than before, but precisely because of that, it's a good range to fire magic.
"Sink them all together... [Thunderstorm]!"
When he cast the high-level magic, lightning rained down from above the foreign tribes that had come near the city walls.
Dozens of foreign tribe warriors were devoured by the lightning all at once.
"Arrows! Shoot magic!"
"Don't let those foreign tribes stick to the wall! They're climbing!"
"Shoot them down! Don't let them into the fortress!"
The other soldiers are also dealing with the enemies coming from outside.
Although the enemy's momentum is strong, things should work out at this rate.
I wondered how things would turn out at first, but... this attack should be manageable too.
"Hmm...?"
However... should I say "it never rains but it pours"?
The anomalies continue.
Only after being certain of victory does the darkness surface so vividly.
"The gate... opened!?"
Yes... suddenly, the fortress gate that should have been closed was thrown open.
It wasn't breached by an attack from outside.
It was opened by someone from the inside.
"You lot! Get inside!"
Several soldiers appeared outside the gate—they were wearing the armor and helmets of the royal army of the Kingdom of Aiwood—and they called out to the foreign tribe warriors.
The surging foreign tribe warriors rushed toward the fortress entrance, as if they had anticipated it.
"Damn...!"
Rest groaned in frustration.
He had forgotten. This tactic had been used since ancient times.
The foreign tribes had infiltrated spies into the fortress beforehand and had them open the gate at the moment of the attack.
It wasn't anything unusual. Rather, it was a cliché tactic worn out by the long history of warfare.
(But... I didn't notice. Because the winged tribe was coming from above, because enemy soldiers were crossing the border river to attack. So I couldn't afford to think about the possibility of enemies inside...!)
He had been completely outplayed.
Just how far had the enemy planned this...? He had fallen right into their trap.
"OOOOOOOOOH!"
"What?! Who opened the gate?!"
"The foreign tribes are coming in!"
Before they could even reassemble their formation, the foreign tribe warriors had already invaded the interior of the fortress.
The inside of the fortress, with friend and foe intermingling, had turned into a crucible of chaos.