A suit of dull, shimmering silver full-plate armor, adorned with beautiful engravings.

Whether there was actually anything inside was unknown; it was impossible to see what lay within the depths of the full-face helm. It was massive in both height and width, possessing a burly, stout, and muscular build.

I'll say it as many times as I have to: boss-class monsters were huge. This one was a four-meter class. Perhaps there was some divine mercy in the fact that they didn't get much bigger than this—since humans likely couldn't defeat them if they did—but even so, it was still a giant.

If I recalled correctly, when something doubles in size, its weight increases eightfold. That would mean this thing weighed well over a ton. It was a literal car. And a car like that was currently swinging a steel sword with all its might.

"F-For now, let's try the same tactic as with Rakshasa: have golems with defensive barriers grapple it! Shamash-san, as soon as you finish your summons, try some magic attacks. Also, Shello-san and Hetty-san, try attacking with your bows!"

At my command, Shello-san and Hetty-san immediately notched and loosed their arrows. The shafts flew straight and true, striking the Guardian and scattering a few shards of light.

The Guardian, however, continued its advance as if nothing had happened.

As Priestess-chan chanted her spells to cast defensive barriers on the golems Shamash-san had summoned, the rocky giants plodded forward to surround the Guardian.

But with a single, effortless sweep of its greatsword, the Guardian sent two golems flying at once. A crystalline shatter echoed as their defensive barriers were destroyed instantly. While the barrier had prevented them from being shattered into pieces, the golems—which should have been incredibly heavy—were knocked back at least five meters.

Seeing that raw physical power, I shouted:

"T-That thing's dangerous! Diana! Priestess-sama, please keep as much distance as possible!"

Rakshasa was a level of strength we could pin down. Baphomet had plenty of annoying attacks but lacked raw power. Cerberus had terrifying charges and bites, but it was stupid. Ifrit primarily used fire and didn't have a weapon, so a punch from him wasn't an instant death sentence.

But a knight this big, swinging a sword that huge, was on a whole different level of danger. Even if it weren't a blade, just being hit by a giant iron bar of that size would kill you.

"Anyway, everyone! Just make sure you don't take a direct hit from that sword! Beyond that, we just have to give it our all as individuals! This is the final monster, so prioritize your lives! Let's do this!"

Ultimately, with this few people, trying to coordinate complex tactics mid-fight via verbal communication was nonsense; we just had to rely on the unspoken understanding developed through training to flow with the battle.

Of course, having Etowa relay the situation from above was helpful, but that was just one piece of information—final judgment and action rested with each person. We were a small party, after all.

Though, the reason we could even pull this off was because we had practiced tirelessly, simulating how to fight in various scenarios together.

The two golems that hadn't been swatted away clung to the Guardian and began throwing punches.

"I'm going too! No retreat, no flattery, no regrets! Charge—!"

The Dullahan, holding its severed blonde head under its arm, raised its lance and, with a scream, charged at the Guardian. Perhaps because it was a summoned beast, it didn't slow down at all and literally crashed into it, which was incredible.

A human could never do that. A suicide charge on horseback.

BAM!

It slammed into it, scraping against the armor.

As if the Dullahan's charge was the signal, the entire team surrounded the monster. Just as we did with the Bear, Shello-san naturally took the role of the tank, while the rest of us poked and prodded with attacks, careful not to get hit.

Since the golems were stubbornly obstructing its path, even the mighty Guardian seemed to have its mobility hampered. Shamash-san fired off a rapid-fire barrage of her signature ice magic. In the meantime, the other two golems managed to get back on their feet and return to the fray.

The golem strategy wasn't bad, but the downside was that the bulky golems got in the way, making it difficult for the rest of us to land our hits. I was hoping we could knock it down and pin it just like we did with Rakshasa.

However, that plan was quickly scrapped.

The Guardian found a momentary opening, kicked a golem aside, and stepped in with powerful lunges, systematically smashing its sword into each target one by one. With every swing, a heavyweight golem was sent sailing through the air.

One hit. Two hits. Three hits. Four hits.

In an instant, with consecutive sword strikes, the golems vanished into light fragments. The Guardian finished its swordplay and held its stance.

"No way..."

The sheer speed of it made my body go stiff with shock.

The golems' only redeeming quality was their strength, but being made of stone, they were supposed to be incredibly hard and heavy. To see them dismantled so effortlessly...

"Shamash-san! Another golem summon, please!"

"Ugh... Right. But perhaps we should call out Ai-chan instead...?"

Ai-chan or Golems? It was a tough call. Even if the golems died quickly, they acted as a wall. They were "expendable" in the best way possible.

But that was it. Our goal wasn't just to stall. It was to win.

"Then let's call out Ai-chan for a bit. If her attacks work, it's better than letting this turn into a war of attrition."

"Indeed... Though, for the record, my magic seems to have almost no effect. The name 'Guardian' isn't just for show, it seems."

The ice magic Shamash-san unleashed was almost entirely resisted. We were already dealing with a lineup of magic-resistant monsters, but this one was exceptionally "hard."

"Alright, please do it. I'm going in too!"

Regardless of everything, I was a swordsman with a magic blade. Theoretically, I should be able to kill it. I had to chip away at its health, even if only bit by bit.

Whirrr!

The giant sword cut through the air. I dodged it by a hair's breadth and swept my blade across its leg.

CLANG!

A few shards of light scattered, but it felt like the armor was absorbing the blow; I didn't feel like I was dealing effective damage. Shello-san, Hetty-san, and Rebecca-san all landed their own strikes, but it felt like we were just gnats biting at a giant.

『Ballista, fire!』

Etowa gave the signal, and Rebecca-san triggered the ballista. A thick bolt—more like a stake—slammed into the Guardian, sending sparks flying.

『Wrecking ball, go!』

We successfully lured the Guardian into position and slammed the iron sphere into it at the perfect time. With a heavy THUD, the ball dented the silver armor, and a significant amount of light shards sprayed out.

Yes! Reliable as always!

I thought, but the joy was short-lived.

The Guardian grabbed the wire, gave it a violent yank, and the entire support structure came crashing down, destroyed.

That was the end of the wrecking ball.

We followed up with more ballista fire. Even if the wrecking ball was gone, there was no point in wavering. It was usually easy to tell when a monster was taking damage because of the light shards, but the amount coming off from the ballista bolts was tiny. The armor was definitely doing its job.

"Here I go, de-arimasu!"

Marina swung her electrified hammer high. Lightning Fountain. She had been saving it for a moment like this—

BZZZT!

The lightning struck the armor and was simply deflected.

"I-It's no good, de-arimasu! It's not doing anything at all!"

It failed. It wasn't the type of attack meant for a boss of this caliber. Since it was an area-of-effect skill, it was more suited for clearing out mobs.

"Fuwaa! I'll kill you, DEATH! Brimming with... EYE!!"

The summoned Evil Eye, Ai-chan, began firing her Death Beams.

As expected of Ai-chan, the beams seemed to be putting out decent damage. The Guardian didn't seem to have a way to attack flying monsters, so it ignored her entirely. She had a free pass to keep blasting. Though, it was also possible the Guardian just had high resistance to the beams and the damage was simply low.

"How's it looking, Shamash-san?"

"To be honest... it's quite bad. That monster appears to be the type that negates almost all forms of magic. Even seventy percent of Ai-chan's attacks are being blocked by that armor."

"Are you serious? Even our physical attacks are barely getting through..."

"My own magic is... it pains me to say, almost meaningless. It's best to rely on the summoned beasts. But Ai-chan's manifestation time is short... Next, I suppose... more golems? I didn't think they were much use in combat before, but I've revised my opinion."

"Power is strength, after all..."

The Guardian wasn't particularly fast. Being a huge armored knight, it's only natural.

Among our summoned beast options, golems were probably the most effective. And we could summon up to four golems. Even if they were killed in one hit, as long as we had magic crystals, having them summoned made a big difference.

Incidentally, the Dullahan was also doing its best, but once it saw its curse magic was ineffective, it basically became a charging machine, only charging. It was dealing some damage, but every time the Guardian's sweep sent it flying, I worried it would disappear. It wasn't human, so it was good that it only scattered light fragments and didn't get cut in half.

It was a useful asset, so it would be a waste to evacuate it like the dragon Morokoshi, but using such a human-like summoned beast as a disposable asset still pained my conscience. Summoned beasts summoned with extra-large magic crystals can apparently be revived if they die, but still...

Regardless, if it had come to this, we had no choice but to grind it down in a war of attrition.

I threw myself back into the battlefield.

...

......

.........

* * *

"............Huh!?"

My consciousness snapped into focus.

Like waking up disoriented and seeing the alarm clock long past the time I was supposed to get up, my blood suddenly boiled.

"How many minutes has it been!? No—how many times has it been, Diana!?"

Diana, who had been peering at me anxiously from the side, answered.

"It's the second time, Goshujin-sama. Forty-five minutes have passed."

"Dammit! Is everyone still alive?"

"Barely... but the Dullahan has died."

"That charging maniac... Well, I heard she can be revived, at least."

I grasped the situation immediately. I must have been brutally taken down by that Guardian and just now recovered thanks to Diana's time-reversal healing magic.

And she said it was the second time. If I hadn't already known her magic worked like this, I probably would have panicked.

Even as we spoke, the sound of clashing steel grew more intense.

Magic circles from Priestess-chan's spells flickered around the Guardian. Shello-san, acting as the tank, was constantly bolstered by a defensive barrier powered by Spirit Stones, while Hetty-san continued to rain down slashes with movements that were far from human.

Compared to the monstrous agility of those two, Rebecca-san, Marina, and I were still very much within the realm of ordinary humans.

"Diana, do we still have Spirit Stones?"

"Yes. We have the ones that dropped from Ifrit as well. However, at this pace, we'll run out in about thirty minutes."

"So that's our time limit...!"

We were out of time.

If we hadn't had the Spirit Stones, we would have been wiped out long ago; Ifrit dropping those stones was a massive stroke of luck. Without them, we'd already be in deep trouble.

The Guardian's magic guard was nearly perfect. Its speed was decent, its attack power was immense, and its reach was long. It was truly a maximum-tier monster. Compared to this, yesterday's Ugallu felt like a cakewalk. If this kept up, it would be a slow death for us.

There had to be... wasn't there some way?

"...Ah!"

"Goshujin-sama!?"

Diana went to speak with resolve at almost the exact same moment I remembered something crucial.

"W-What is it, Goshujin-sama?"

"I totally forgot that Mugen-san taught me a powerful magic. I guess I got too heated up in the fight."

"Magic? But magic against that thing is..."

"No, this is one that was considered the strongest during the era of Spirit Civilization. I don't know if I can pull it off, but I've gotta try."

Magic is triggered by understanding "The Law."

That's why Mugen-san and I spent all that time studying. My studies ended halfway, but since I still had the support skill 『The Principle』, it should probably activate.

In fact, I'd managed to trigger it during secret practice. I'd kept quiet about it because I wanted to surprise everyone, but once the battle started, my head was just too full of sword fighting.

『Etowa, I'm going to use a massive magic now. It's harmless to allies, but announce it over the mic just in case.』

『Roger!』

I closed my eyes and began constructing the magical formula in my mind.

A magical formula... or rather, a chemical formula.

Magic doesn't trigger unless the logic makes sense in your head to a certain degree. I had no way to check, but there's a concept of internal mana—what you'd call Magic Points or MP.

Since my MP shouldn't be high, this was a one-shot deal. I'd confirmed before that I couldn't use it twice in a row.

I built the equation in my mind, visualized the effect, and synthesized the materials from mana. It was all a matter of imagery. If the image was weak, the magic wouldn't trigger. Normally, you need absolute conviction for it to work, but with my assist skill, this should be enough to scrape by.

2C₇H₅N₃O₆ → 3N₂ + 5H₂O + 7CO + 7C.

The formula I'd hammered into my brain over and over.

How many years has it been since I did science? Mugen-san had actually laughed at how bad I was at it.

"Here I go!"

I refined the mana and unleashed the magic.

A simple, ridiculous, yet powerful spell that converts one's own mana into TNT and detonates it.

"TNT Burst!!"

I felt the mana drain from my body, and simultaneously, a glowing orb of fire was born right in front of the Guardian's eyes.

Along with a blinding light, the golden fireball expanded in a flash and exploded. The boom and the shockwave vibrated in my chest even more than Cerberus's roar.

A moment later, a heavy thrum of the earth reached us.

An attack magic that was considered essential for veteran players during the Spirit Civilization era.

—The TNT Explosion magic.