Alright, Sukuna admitted, he could not, in fact, afford to underestimate these automatons. The thought passed his mind as he had to regenerate his left arm, chest, and leg for what must've been the... oh... eleventh time? He'd stopped counting after a while. Sukuna gritted his teeth as he burst through the side of a mountain, having been hurled through the damn thing when one of the Iron Soldiers blew itself up in an epic explosion of force and fire, powerful enough to crunch and pulp his muscles and bones, even through extreme physical augmentation and spell-defenses, which was honestly rather surprising, since – as far as Sukuna was aware – none of the weapons arrayed against him had been exotic in nature.
This was becoming annoyingly tedious and, if he was being honest, a bit dangerous, even for him.
The Iron Soldiers all utilized either kinetic or thermal forms of energy as their primary means of offense, but on a level far beyond anything he'd ever faced in open combat before. Those crimson beams of theirs burned hot enough to carve open the faces of mountains and those... strange metal fireworks of theirs moved so fast that he could just barely dodge them and, even then, they exploded upon impact with anything, resulting in a fiery explosion not unlike the one that'd sent him through a damn mountain, through hundreds of tons of solid rock, and out the other side. And the worst part, Sukuna mused as he stood up and stretched his limbs, Dismantling hundreds more of the seemingly numberless Iron Soldiers in a single, fell swoop, their chests falling out from their torsos as the King of Curses targeted their cores, figuring out, early on, that the annoying machines weren't going to die unless he destroyed that part of them... where was he? Right, the worst part was that it seemed like the surface of the entire planet was covered in these machines.
He was strong, Sukuna knew that much. He was more powerful than anyone he'd ever come across, including the likes of Tengen and Kenjaku, but boy oh boy... not even the King of Curses can wage war alone against an entire world, against millions of murderous machines that, individually, would've been more than a match even for the upper echelons of Jujutsu Society. And here he was, engaged in a fight against millions of them. And, despite all of that, Sukuna would be lying if he said he wasn't enjoying himself.
A rush of Iron Soldiers streamed towards him through the hole in the mountain, forcing themselves through an incredibly narrow passageway that, frankly, only managed to slow them down. Sukuna grinned as he held out his left hand and gathered an obscene amount of Cursed Energy, which he then rapidly condensed. "Open."
Fire roared to life around him, the Flaming Arrow of Amaterasu appearing between the pointer and middle fingers of his left hand. Cursed Fire burned hotter than any lightning, nearly as hot as the sun itself, but it did not burn him, even when the land around him liquefied and melted as Sukuna drew the blazing arrow, an artifact he'd plundered off the corpse of a long dead god. And, when enough of the Iron Soldiers had piled over each other, Sukuna released the arrow of fire. Time seemed to slow to a near crawl as the cursed projectile sailed across the open air, hissing. The Iron Soldiers that were closest to it began melting even before the arrow reached them. A curiosity, Sukuna thought, considering they were more than capable of surviving the heat of their crimson beam attacks.
And then, the arrow touched one of the Iron Soldiers and detonated. A wave of fire, ash, melted stone, and super heated winds exploded and immediately engulfed the base of the mountain, cracking and rending stone apart. Hundreds of Iron Soldiers perished immediately, consumed by the flames and melted into oblivion. Sukuna grinned as he leapt back, a rain of molten metal showering the spot he'd stood upon. The fires of the Flaming Arrow of Amaterasu weren't exactly physical in nature. Oh, certainly, they had the power to melt stone in seconds and turn great fields into glass, but the heat it produced was of a spiritual nature, fueled by an immense amount of Cursed Energy, enough for at least ten uses of his Domain Expansion. Unlike physical heat, which was limited, spiritual heat had a tendency to ignore the laws of physics, which was to say that things that weren't supposed to melt or catch fire, suddenly found themselves melting or catching fire, simply because Cursed Flames didn't care.
The Iron Soldiers were likely resistant to heat, given their choice of weapons, but Cursed Fire was different and the only way they could've possibly defended themselves against it was through Jujutsu. And, unless Sukuna's understanding of the nature of Jujutsu was sorely mistaken, then it was simply impossible for machines to truly or properly utilize Cursed Energy; there were exceptions, of course, such as automatons that were created precisely through sorcery, but the Iron Soldiers seemed to be purely physical beings and nothing more.
A thunderous crack echoed as the stones that held up the mountain broke apart in the heat and the rapidly-expanding forces. And then, like shogi pieces that were stacked too high, the mountain began to collapse, creating a gargantuan avalanche of massive boulders, pebbles, sharp stones, and great clouds of dust and smoke. He couldn't tell how many of them were destroyed in there, but a collapsing mountain surely wasn't something they could just walk off and ignore. Sukuna grinned as he jumped even further back, only to be immediately assaulted by more Iron Soldiers, ones who were smart enough not to crawl after him in such a narrow tunnel.
"You guys just keep coming, huh?" Sukuna muttered, Dismantling hundreds of them at once in a circular area around himself with but a simple gesture. Hundreds more immediately took their place. Sukuna then bounced around crimson beams and fire rockets came for him. His grin did not fade. "But, I guess I can't complain; I'm having a little too much fun, honestly!"
Another crimson beam struck him from a blind spot, a risk that came when one was as hilariously outnumbered as he was at the moment. A portion of his stomach simply ceased to exist, burnt to ashes and dust in an instant; the damage also sent his right leg hurling down, bone and flesh and all. Sukuna's grin widened as he applied a quick burst of Reverse Cursed Energy to mend the damage almost immediately; his mastery of the technique meant its efficiency did not suffer, regenerating more than what he spent, which meant he could spend the rest of the day just tanking shots from the Iron Soldiers if he felt like it. Of course, he wouldn't actually do that, because that would be boring and incredibly dangerous, since a lucky shot to the head meant the end and that... wasn't a good way to die, honestly.
Sukuna glided briefly across the air, before landing on the side of a steep cliff, whereupon he pushed himself off and surged towards the Iron Soldiers, breaking the sound barrier as he launched dozens of Dismantles, all the while hundreds of crimson beams and rockets came after him and missed their mark, veering off into the sky or right into another blob of Iron Soldiers. Sukuna then tore into a gathering of them, wading into their ranks and attacking left and right with his fists alone, punching into their armored forms one after another. This way, he noted, the Iron Soldiers hesitated in the usage of their crimson beams, likely in an effort not to kill each other by accident and further depleting their own numbers.
Sukuna's right hand reached out and tore into the chest of an Iron Soldier, before he then took hold of its core and ripped it right out and hurled it through the chest of another. More and more of them gathered around him. The logic, he figured, was sound. They couldn't defeat him one on one and so they resorted to swarming him with large numbers. A metallic hand pierced through his shoulder, but Sukuna merely sliced the hand apart and closed the wound with an immediate application of Reverse Cursed Energy. As the gathered blob of Iron Soldiers grew, Sukuna chuckled and brought his hands together, "Domain Expansion: Malevolent Shrine!"
Time seemed to slow to a near-halt as his Cursed Energies rapidly expanded outwards, engulfing two hundred meters of open air and about eight hundred or so Iron Soldiers. In his domain, he and he alone was king. And the metal automatons could do nothing as Dismantle sliced all of them apart into ribbons with a thousand cuts each. The trade off, Sukuna mused, for Malevolent Shrine's instant hit ability was that each slash of Cleave or Dismantle was only about a fifth as strong as ones that were done outside the domain. It took only three seconds to destroy every single Iron Soldier within the range of Malevolent Shrine, after which Sukuna immediately deactivated the domain, seeing as he couldn't just expect all of the Iron Soldiers to walk in like a bunch of idiots. After all, the automatons were slowly adapting to his tactics, analyzing patterns and putting a stop to them whenever possible. Their only weakness was that he did not fight with patterns. Sure, they'd adopt to some of his moves, but machines could only do so much before he sliced them apart.
By then, the battlefield was riddled with the corpses of the Iron Soldiers, cut down to tiny pieces and scattered about. Sukuna breathed in, enjoying the very brief window of respite. He must've already killed thousands of them by now and, unless he was planning on taking on every single one of them until there was nothing left, then he had to change up his game. Or, he could do just that; either way, he'd end up having a lot of fun. He just wished there was some variety to the Iron Soldiers. The monotony of his enemies made this fight just a tiny bit bland, in his expert opinion. Where were the-
The ground shook and the Iron Soldiers that'd gathered to swarm him suddenly stopped, before gradually retreating. As they did, Sukuna shrugged and Dismantled a few hundred more.
Very briefly, he caught the featureless black disc reappearing just under the clouds. "Level 1 response units inefficient! Escalating to level 2!"
Oh.
That meant they still had a bunch of good stuff just lying around. They recognized then, Sukuna mused, that he was a much greater threat than they initially estimated and had, as the disc so blatantly declared, escalated to a, hopefully, stronger and greater army. Sukuna grinned, feeling giddy. Ah, this was the life. Fight strong opponents, get challenged, and win or die trying. What else was there? Not even the flesh of a thousand humans, cooked to perfection by Uraume, could compare to the cathartic sensation that was the chaos of a battlefield. However, if the machines were going to escalate, then so was he.
After all, he didn't live as long as he did by being only a master of one trick. He knew a lot of tricks. Some were more dangerous and more powerful than others. Ah, how fun this was, to be pushed to the brink, to be forced to bring out all that he had against a foe that knew no fear, no hesitation, didn't retreat, and did not run out. If he was going to die here, then he'd die a very satisfied man. But, of course, death can have him when it earns him; until then, he was going to keep terrorizing the cosmos.
Sukuna's eyes widened as the mountains around him broke apart, collapsing into great mounds of rubble and ruin. He leapt upwards as the earth tore open beneath his feet. He landed a fair distance away, atop a plateau that overlooked the shattered mountains. And there, he saw, rising from the smoke and dust, giants of iron.
No, not giants.
Titans.
One climbed out of the earth and stood at a height of over eighty meters, its body made entirely of metal, its arms comprised of weapons the size of castles - some bore swords, others carried spears, and a few held massive tubes of some kind, likely to release some sort of projectile. And there were at least five of them, right in front of him, causing the very ground to dance and shake.
"Oh boy." Sukuna grinned, bringing his hands together. "What a treat!"