Isis's suggestion made Altaïr's eyes light up.
Forcing the Teppeki Shen Gaoren to overheat until its barrel exploded? That was indeed a good idea.
Even if it did not work quite as perfectly as they hoped and blow the Teppeki Shen Gaoren apart outright, the creature clearly could not maintain that overheated state indefinitely.
The reason was simple.
When they had first encountered the Teppeki Shen Gaoren at the volcano, it was already overheated. It had resembled an erupting volcano, its entire body glowing red-hot as it spewed lava. Molten, superheated body fluid had streamed from gaps in its shell, leaving blooming crimson scorch marks across the ground.
Its obvious instability was one issue, but more importantly, it was constantly losing matter.
Energy could be compressed or converted, but matter could not appear from nowhere. The chunks of lava it sprayed and the magma flowing across its body, whether secretions or body fluid, were finite in quantity.
Without replenishing them by feeding or some other means, those substances would eventually run out.
According to the Professor's theory, spewing magma and secreting molten material might be the Teppeki Shen Gaoren's equivalent of sweating, a way to shed excess heat.
Once that lava-like body fluid was exhausted, with no large body of water nearby to cool it rapidly, the more thermal energy it stored, the more dangerous its condition would become.
Altaïr motioned for his companions to gather around. "Nymera, stop firing Flaming Ammo at the joints. Aim directly at the torso and drive its body temperature even higher.
"Isis, you too. Overheat your Gunlance and use high-temperature attacks against it. The heat will soften its shell.
"But both of you need to be careful. Your own safety comes first. A splash of that magma is no joke.
"We still have two days of travel ahead. Don't give it a chance to 'cool down'!"
The Hunters acknowledged the order and quickened their pace in pursuit of the red-hot Teppeki Shen Gaoren.
Before they even drew close, a scorching wave of heat rolled over them, making them feel as though they had returned to the depths of the volcano.
They immediately downed Cool Drinks to ease the heat, then pressed on through the sweltering air.
Using the momentum of his charge, Altaïr drew his weapon and brought another swift Overhead Slash down on the Teppeki Shen Gaoren's leg. The heavy blade biting slightly into the shell sent a thrill through him.
As expected, the red-hot shell had softened!
Before he could smile, however, Morgan shouted a warning from behind him. "Watch out! Above you!"
Without thinking, Altaïr rolled backward as fast as he could, catching a glimpse of what was overhead from the corner of his eye.
A splash of dark red lava poured down. It was not a large amount, roughly one of Isis's dinner bowls' worth, and it was scattered widely enough that little of it would land on him.
It was still lava. Any that touched bare skin would cause severe burns in an instant.
As he sprang to his feet, he raised Tyrant Blade [Heaven Swallower] in Great Sword form above his head, using it as a shield against the lava that pattered down like loose gravel.
"Sorry!" Morgan called out again. "From now on, I'll only fire once you're clear!"
Altaïr immediately understood what had happened.
Morgan's Sticky Ammo had probably blasted that small amount of lava from the gaps in the Shen Gaoren's leg joints.
When it was not red-hot, a Gunner and Blademaster could attack it at the same time without issue.
Now, however, they had to be far more careful.
Altaïr swung Tyrant Blade [Heaven Swallower] onto his back, then drew the blade from its sheath, switching the weapon back to Long Sword form.
At the moment, the Long Sword's agility mattered more than the Great Sword's heavy blows.
He threaded nimbly between the Teppeki Shen Gaoren's four legs as they moved in turn. The instant one of its front legs came down, he arrived beside it.
Step Slash, Rising Slash, Thrust...
One basic sword technique followed another.
To conserve his stamina, Altaïr did not activate Demon Mode, nor did he intend to use any of his more powerful sword techniques.
With the shell softened, even these ordinary attacks could leave marks on the Shen Gaoren's armor. The damage was slight, but it was better than nothing.
Across from him, Isis seized the opening to hurry into position and bring up her Glavenus Gunlance and Large Shield, hoping to make the Gunlance red-hot as quickly as possible.
After more than a day of constant attacks, they knew the Shen Gaoren's stride length and cadence by heart.
"Wyvern's Fire!" Isis shouted in warning as she pulled the trigger. Searing energy gathered at the muzzle.
The instant Wyvern's Fire began charging, the Shen Gaoren's right front foot slammed down barely two meters in front of her.
None of the others would have dared approach so closely the moment its foot landed. The violent tremor would have thrown them off balance or even knocked them down, and another leg coming down afterward could easily prove fatal.
Isis did not have to worry about that. She was exceptionally stable in her braced stance, and the Zamtrios Z Armor Set's excellent tremor resistance allowed her to hold her ground beneath the Shen Gaoren's foot and finish charging Wyvern's Fire.
"BOOOOM!"
Wyvern's Fire erupted from less than half a meter away, its devastating explosive flames slamming into the Teppeki Shen Gaoren's right front leg, already covered in dense slash marks.
Under the tremendous impact, the dark red patterns on the Shen Gaoren's leg flared. Altaïr instinctively shouted, "Watch out!"
At the same instant Wyvern's Fire struck, a broad spray of lava burst from the gaps in the Shen Gaoren's leg shell and the weakened areas crisscrossed with slash marks, raining down on Isis.
The powerful recoil sent Isis sliding back two or three meters. Keeping her center of gravity low, she raised her Large Shield overhead.
The shield blocked most of the lava, and only a tiny amount splashed onto her legs and feet. Thanks to the Zamtrios Z Armor Set's equally impressive heat resistance, she was unharmed.
Isis's heart hammered. Thank goodness she had not overestimated herself and attempted the unfamiliar new technique, instead firing Wyvern's Fire from the standard braced stance.
Otherwise, the eruption of lava might have seriously wounded her.
The magma blown loose by the Sticky Ammo, together with what had just happened to Isis, set alarm bells ringing in Altaïr's mind. The Teppeki Shen Gaoren might not have been actively counterattacking, but its extreme body temperature was itself a defensive measure.
Its ability to spew magma from its wounds whenever it was struck made every attack against it far more dangerous.
As for why none of his own slashes had produced magma... well, he probably had not hit hard enough for the Shen Gaoren's body to react...
Then again, Sticky Ammo and Wyvern's Fire were both designed to break armor. It was only natural that his basic sword techniques could not compare. In fact, that was good news; being able to damage the Shen Gaoren's legs continuously without triggering an eruption was ideal.
"Whoa!"
Just as Altaïr was reassuring himself, a startled cry came from Isis's direction.
While circling for his next opening, Altaïr glanced over and saw Isis swing her red-hot Gunlance. With one simple horizontal sweep, she sent another sheet of lava splashing out.
She immediately leaped back, avoiding the lava as she shouted, "Watch out! This thing erupts at the slightest touch now!"
At the slightest touch? Did that mean it had grown even more active?
Puzzled, Altaïr saw the Shen Gaoren's left front leg come down. He seized the opening, rushed in, delivered two consecutive overhead slashes, and immediately used Foresight Slash to retreat.
Nothing happened.
Altaïr took a deep breath.
That line of thinking had been too timid. It was wrong. How could he focus only on safety?
Before the Shen Gaoren launched a true counterattack, they needed to force it to lose as much magma-like body fluid as possible. That would make it easier to repel!
He raised his Long Sword and entered a focused stance.