The fleeing boy attracted the attention of more monsters. Sighting living prey, they abandoned their dead meals and raced after him like starving wolves.
Hovering in the air, Shirou readied himself to intervene.
The fish monsters seemed to sense his gaze. They turned as one to look up at him, eyes filled with savagery and greed, vocalizing shrieks. Their fish-like maws split open into hundreds of barbed fangs that glinted ominously even in sunlight, leaching warmth from the very air.
They saw Shirou as food too. Crouching briefly, they shot upwards like bullets headed straight for him.
Seeing this, Shirou's expression hardened. Rhongomyniad materialized in front of him and he grasped it, the tip incinerating the first monster to make contact with a crunching noise. He condensed Rhongomyniad's lance form into a long, slender spear before diving like a hunting falcon into the throng of monsters.
He didn't unleash the spear blast and beam. By A-146's account, as Skadi's frozen seal weakened, this frozen sea was also going to slowly melt. Using the beam would only accelerate the process due to its searing heat and awaken more monsters trapped in the ice.
Instead, Shirou dove among the sea monsters, his Spear of Endless Light lancing out repeatedly to cleanly slaughter them in droves.
After training under Scathach, his spearmanship was no longer that of a total beginner, even if it wasn't the best out there.
And Rhongomyniad, the spear of endless light, was very powerful. Its condensed form showed mastery over the spear that went way beyond what even Vortigern and Artoria could do - a shape only Shirou could wield.
Every thrust was like hundreds of deadly flower petals spraying out. With the spear's insane power added to that, anything it touched meant injury, and anything it struck meant death.
"Boom, boom..."
Explosions kept going off. Bodies covered the ground, the blood dyeing the earth while guts soiled the clean snow.
The ground rumbled with the sound of cracking ice as hordes of ferocious sea monsters burst through. These creatures, just freed from the frozen sea, were pretty sluggish in movement, but the overpowering scent of blood made them excited like a cat catching a whiff of fish. One after another they emerged, ravenously devouring everything on the icy surface and not even sparing the corpses of their own.
Shirou cut them down one by one, but with their vast numbers, it would take a Noble Phantasm to wipe them out quickly.
Just then, Sigurd and Salter showed up to help. Shirou warned them against using their Noble Phantasms. They both nodded in understanding and jumped into battle, swords in hand.
Sigurd shielded the boy behind him then started slashing through the horde of approaching sea monsters. With Sigurd's broad back protecting him, the boy felt a little safer.
The battle intensified, the ground saturated with blood. Crazed by the scent, the monsters attacked with even wilder frenzy, relentlessly throwing themselves at Shirou and the others.
Shirou's brow furrowed in annoyance. As a support-focused Heroic Spirit, he wasn't built for close combat. The endless waves of suicidal attackers exploited that weakness, gradually overwhelming him.
"So it's a battle of attrition, huh?"
He raised an eyebrow. Time to call in some backup.
With a flick of his wrist, the spear spun before shifting into Caliburn. Gripping the hilt, he raised the blazing blade high. It shone like a star and then he slashed down in a blinding arc—
Light roared and thundered!
An avalanche of snow burst outward as the dreary sky split open.
Carved into the snowy landscape was a fissure shaped like a soaring dragon.
Having driven back the monsters around her, Salter glanced over, frowning. "Eternal King, What're you doing? I thought you said no Noble Phantasms?"
"I'm sounding the war horn."
No sooner had he spoken than azure lightning crackled along that carved furrow.
Magical energy surged and swelled.
Sigurd's brows furrowed. "What is this...?"
The figure of Iskandar flashed through Salter's mind and her face warped in shock. "The King's Army?!"
As she spoke, forms began materializing amidst the crackling fissure. A legion took shape, five hundred strong, assembled across the icy landscape.
They wore shining silver armor and wielded demonic spears engraved with runes. Upon appearing, the troops raised their spears high, gazed at Shirou with fevered eyes and roared:
"We heed the King's call!"
Though only five hundred, their combined voices thundered with earthshaking force, overflowing with mankind's indomitable fighting spirit.
Salter murmured in wonder, "It really is... the King's Army?"
She unconsciously lowered her sword, shaken by their presence though they numbered only five hundred strong.
For if this was Iskandar's Ionian Hetairoi, the embodiment of his army, then what stood before her now represented the eternal glory of Shirou's kingdom.
It was also what Salter had always yearned for, had struggled all her life to achieve.
Shirou raised his spear and pointed at the sea monsters. "19th Legion! We march to war!"
"To war!" the five hundred roared, their fighting spirit echoing through the skies.
Shirou led the charge, crashing headlong towards the enemy. These sea monsters numbered barely over two thousand, exhausted from breaking the ice. Against five hundred tireless Heroic Spirits, they didn't stand a chance.
Though outnumbered four to one, Shirou's 19th Legion smashed into the sea monster formation and tore through their ranks like tigers among sheep, easily routing the superior numbers.
The frenzied beasts could have fled, but crazed by the blood, they abandoned all reason and fought to the last.
"Who are the real monsters here?" Salter muttered.
Sigurd watched on gravely. To be frank, he was shaken by Shirou's summoned army. If Odin had commanded such forces during Ragnarok, perhaps the old gods would still reign supreme.
But history could not be altered. This army belonged solely to Shirou.
The legendary 19th Legion tore through the monsters until none remained, slaughtered to the last creature.
In truth, the beasts could have retreated or escaped. But driven berserk by the blood soaked snow, they lost all reason in their madness and fought to the death against the Legion.
When the massacre ended, Shirou's forces emerged unscathed. This was only to be expected, as they had been manifested through his First Noble Phantasm, "The Hour of Decisive Confrontation Has Come: I Am the Vanguard of the Century." That Noble Phantasm also carried the legend of the king's burden - any harm done to the army would instead be transferred to Shirou.
Unfortunately for his enemies, Shirou also had Avalon, so all wounds and injuries inflicted on him would immediately heal. To break through Shirou's first Noble Phantasm, then, one would first need to defeat Shirou himself. And to defeat Shirou, one must first penetrate through his army and the protection of Avalon, then strike him down in a single blow. So only those on the level of an Outer God would likely be capable of such a feat.
Of course, there was also the option of slowly draining all his mana. Eternal King was indeed powerful, but also a massive mana glutton with immense expenditure. But now, Shirou possessed an inexhaustible abundance of mana!
After annihilating the first wave of unsealed sea monsters, Shirou instructed Salter and the others to withdraw, lest more beasts be drawn by the lingering scent of blood.
He chose not to dispel his 19th Legion, allowing the five hundred Heroic Spirits to remain manifested. It would spare them from clashing against the next wave of emerging horrors.