When someone thought of space-time ninjutsu, the most common example would be the Summoning Jutsu
But ordinary summoning jutsu wouldn't help in this situation. To escape the current predicament, he needed to find a way to bring himself back to his original world. I need to reverse summon, bring myself back and seal the mural. No pressure, right?
Without a doubt, the mural that the monster entered is the root of all this. And to achieve this, he first needed to regain his ability to cast jutsu normally.
Right now, Jiraiya is constrained by the rules of this two-dimensional space, where only ninjutsu with simple hand seals can be used.
This world has unique rules, allowing objects to exist only in a state parallel to the world. For example, a person's hand can overlap with the body, but it cannot deviate from the plane where the body is located. Any deviation from the plane will cause that part to be erased.
This makes most ninjutsu hand seals impossible. But there is one jutsu that can be performed without violating the rules of this world.
"Barrier: Toad Gourd Prison!"
He made a hand seal with one hand, and the next second, he found himself in a massive, fleshy, red space.
This technique summoned a gourd toad from Mount Myōboku. Strictly speaking, it wasn't a summoning jutsu, but a type of barrier technique.
This ninjutsu could pull both oneself and the enemy into a vast, isolated space, which was actually the stomach of the gourd toad. In this space, one could hide without being detected from the outside. This place was considered an independent space.
The liquid in this space, which looked like lake water, was actually the gourd toad's stomach acid, and anything that fell into it would quickly dissolve. More importantly, this space was three-dimensional, allowing Jiraiya to freely cast ninjutsu.
"Finally, some comfort," Jiraiya said, rotating his stiff shoulders and neck. The two-dimensional world's rules, with only left and right but no forward or backward, were incredibly uncomfortable for a human body.
However, the crisis was not over. He had only pulled himself into an alternate-space barrier. But the gourd toad itself had not escaped the two-dimensional space where the monster resided.
At this moment, the gourd toad was confused, staring at the gray-green land around it. When it tried to leap forward, it kept jumping to the right. Jiraiya was essentially inside a three-dimensional barrier summoned within the two-dimensional space. While he existed in three dimensions, the three-dimensional space itself remained within the two-dimensional one, meaning Jiraiya had not fully escaped.
A pocket dimension inside a 2D world. It's like hiding a sphere inside a painting, he appreciated the irony of his situation.
But this was enough. All he needed was a space where he could use ninjutsu normally. Time to call in the cavalry.
He quickly made hand seals with both hands and slammed them onto the ground. In a puff of smoke, two small toads appeared. One was a green toad with a gray cloak, and the other a purple toad with a black cloak.
"Pa, Ma, how are you?" Jiraiya greeted.
Although small, these toads were none other than Fukasaku and Shima, the trusted aides of the Great Toad Sage and elders of Mount Myōboku.
"Jiraiya-boy, what kind of mess have you gotten yourself into this time?" Shima asked.
"Oh, you know, the usual. Trapped in a painting. Chased by monsters, not women this time," Jiraiya replied with a forced chuckle. "Why don't the two of you take a look outside?"
Fukasaku and Shima placed their hands on the ground, on the floating island inside the gourd toad's stomach, and immediately connected to the gourd toad's sensory system. They saw what the gourd toad was seeing.
After observing for a moment, the two sage toads quickly sensed something was off. The oddness was obvious. Since a toad's body is not as flexible as a human's, it cannot move sideways without changing its orientation. But under the toads' perception, every time the gourd toad jumped forward, its body moved sideways instead.
This illogical behavior felt as if a powerful spatial force was forcibly altering the gourd toad's movement. "In all my 800 years, I've never seen anything like this," Fukasaku muttered.
"What kind of space is this? Why can the gourd toad only jump to the right, and not forward?" Shima asked.
"This is a two-dimensional space. The spatial rules in this world only allow for left and right; there is no forward or backward. Any forward movement is replaced by left or right," Jiraiya explained grimly.
Although they didn't fully understand, Fukasaku and Shima nodded.
"I'm trapped in this space right now, so I had no choice but to summon you both for help."
"My idea is to end the summoning soon and send you both back to the real world, where you can use reverse summoning to bring me back to the real world."
Jiraiya's plan was to have the two sages use reverse summoning to bring him back to the real world. However, the reverse summoning location needed to be at the mural near the mansion. He had to quickly seal the mural to prevent hundreds or even thousands of these monsters from crossing over into the real world.
Soon, the two toad sages understood his plan. Fukasaku insisted on staying, while Shima, after learning the mansion's location, ended the summoning and disappeared in a puff of smoke.
Now all Jiraiya had to do was wait patiently for Shima to reach the location in the real world and perform the reverse summoning to bring him back.
While waiting, Jiraiya and Fukasaku watched the situation outside through the gourd toad's vision. With it as bait, the monsters didn't return to the real world but continued searching around.
These monsters weren't very intelligent and had no idea where Jiraiya had vanished to. "They're not the brightest bunch. Good for us, I suppose," Jiraiya commented.
Although the barrier jutsu could block sensory detection, it only hid his presence, not the gourd toad itself. There wasn't much else in this space, and any ninja with a bit of sense would realize that the red toad on the ground was likely where Jiraiya was hiding.
But these monsters just couldn't figure it out and continued blindly searching around the gourd toad. "Jiraiya, do you think this is the kind of power the Great Toad Sage prophesied?" Fukasaku asked.
He couldn't understand these bizarre creatures and attributed them to the unknown power in the Great Toad Sage's prophecy.
"I don't know," Jiraiya shook his head, then added, "But at least it shows that this world isn't as simple as we thought. There are many things beyond our understanding."
"Maybe, just as the Great Toad Sage prophesied, we are just living on a small island surrounded by darkness, and there are many unknown and powerful beings in the vast ocean beyond."
"How about we use this waiting time to catch one of the monsters?"
Fukasaku's eyes widened in surprise. "Are you sure that's wise, Jiraiya-boy?"
Jiraiya grinned. "Probably not. But we need to understand what we're up against."
If a monster stands in front of an object being pulled into this dimension, the monster will never be touched, as the world in this dimension has no rules of front and back. In other words, monsters in this dimensional world are invincible.
These monsters' bodies can ignore the rules of space and touch any object at will. But now, as these monsters search for Jiraiya, they all scatter.
Wait... if they're on the same plane as the toad... It can touch these monsters! We might have a chance! He turned to Fukasaku. "Pa, I think I've got an idea."
As long as one monster can be dragged into this three-dimensional space, it won't be that difficult to deal with anymore. Based on the brief encounter in the real world just now, Jiraiya discovered their vulnerabilities.
"They shrugged off fire like it was nothing," he recounted, "but physical attacks... they felt those."
Fukasaku stroked his chin thoughtfully. "Perhaps their connection to our dimension is more tenuous than we thought."
Additionally, these monsters are quite unintelligent. Even if he drags one into the gourd toad's belly right in front of them, the other monsters won't notice.
This is the advantage of ninjutsu: while humans cannot understand these strange monsters and the world they inhabit, the monsters also cannot comprehend human ninjutsu.
"Ready, Pa? We might only get one shot at this," Jiraiya said to the nearby Fukasaku.
Fukasaku nodded, then infused his own sage chakra into his tongue. His tongue quickly extended towards a massive black hole at the top of the barrier space.
In the two-dimensional space, thousands of monsters were gathered around the gourd toad and the mountain of corpses, searching.
Suddenly, one of the monsters, just aligned with the gourd toad on the same plane, was grabbed by a pink tongue extending from the gourd toad's mouth, wrapping around its leg and forcefully pulling it toward the gaping mouth of the gourd toad.
Although the monster instinctively dug its claws into the ground, the strength of the tongue was overwhelming, dragging it into the gourd toad's mouth.
Once the monster was completely pulled inside, the gourd toad immediately closed its mouth as if nothing had happened.
However, one nearby monster reacted sluggishly, turning its recessed eyes toward the spot where the other one had disappeared. Its head slowly followed the trace of the monster being dragged, finally locking its gaze on the gourd toad on the ground.
It slowly walked over, shaking its head, and though it had no eyes, it seemed to have noticed the gourd toad's presence.
Inside the gourd toad's barrier space, a gray figure dropped from the black hole above and fell into a massive lake of stomach acid.
Though the lake wasn't deep, the monster didn't sink but floated on the brownish-gray surface. After a few seconds, the hunched, gray body of the monster struggled to rise.
Monsters shouldn't have chakra, so naturally, they couldn't stand on the water like a ninja could. But this monster was indeed standing on the lake, and for it, the stomach acid seemed to be solid ground.
Moreover, its upper body had been fully submerged in the stomach acid, but after standing up, Jiraiya noticed that the acid had done no damage to the monster at all.
Not just fire—acid had no effect either. This realization sent a shiver down Jiraiya's spine. The deeper he engaged with the monster, the less he understood it.
It was immune to fire, resistant to acid, able to travel between two-dimensional and three-dimensional worlds without being affected, and lived in a bizarre dimension beyond comprehension. All of this was far beyond what could be understood.
If this isn't what the old sage meant... what could possibly fit that description? Jiraiya remembered the Great Toad Sage's ominous prophecy.
Jiraiya and Fukasaku stood on the floating island, watching as the monster slowly climbed out of the lake. After scanning its surroundings, the monster spotted Jiraiya on the floating island and immediately charged toward him.
"Jiraiya! On your guard!" Fukasaku shouted, dropping into a fighting stance.
Back in the dark hall of the mansion, Jiraiya hadn't sensed its speed so clearly, but now in the barrier, he realized the monster was much faster than expected.
"Pa, we need to end this quickly. We don't know what other tricks it might have."
"Agreed," Fukasaku replied grimly. "Let's show this little one the power of sage arts!"
Though the monster's beast-like strides lacked grace and seemed on the verge of losing balance, its body never faltered, rushing forward with a speed not inferior to a jonin.
Jiraiya and Fukasaku prepared themselves. While the monster's body was strange, Jiraiya had already confirmed its weakness to physical attacks.
"Wild Lion's Mane Technique!" he shouted, his hair spreading out, extending from all directions to grab the monster.
Although the monster struggled violently, Jiraiya's strength held firm, keeping it in a stalemate.
"Pa!" After restraining the monster, Jiraiya shouted immediately.
"Got it!" Fukasaku nodded, and once again, a long pink tongue shot out from his mouth.
This time, however, the tongue wasn't as long, but its hardness was extreme, as powerful as a blade slicing toward the monster's head.
The monster's head was instantly severed and caught by Jiraiya's hair, along with its immobilized body, pulling them both toward the floating island.
On the island, Jiraiya released his technique, laying the body and head at the edge of the island, as he and Fukasaku carefully examined the monster's corpse.
The monster's skin appeared gray and wrinkled, feeling like dried, old tree bark, yet it possessed remarkable toughness, like rubber.
But the most striking discovery was in the cross-section of the monster's body and head. Inside, Jiraiya and Fukasaku saw something even more incomprehensible than the skin.
The monster's body was completely empty!
Jiraiya and Fukasaku rubbed their eyes, and after confirming they weren't imagining things, they looked again at the cross-sections of the head and torso.
But there was nothing inside.
"This... this shouldn't be possible," Fukasaku muttered. Is it a puppet? Where are the strings then?
Not only that, the skin, which had been stretched to form the monster's shape, began to deflate, just like a balloon losing air.
As they watched the empty body slowly deflate, both Jiraiya and Fukasaku's minds fell into a trance. In this dazed state, a word surfaced in both of their minds.
Although they didn't discuss why this word had suddenly emerged, there was no doubt that it was the perfect name for the monster before them.
Dimensional Shambler.