The dense night of the Demon Slayer world was a stark contrast to the lantern-lit nights of Konoha; the smell of blood and the cold air confirmed the nature of the place.
Gojo Satoru, unfazed, watched the scene unfold before him: Tanjiro Kamado, in his checkered haori, valiantly fighting a red-skinned, horned demon.
"Water Breathing, First Stance: Water Surface Slash," Tanjiro shouted, his Nichirin blade slicing through the air with grace and precision, an invisible whirlwind of water materializing with each movement. The demon groaned, but his wounds healed with alarming speed.
Interesting, Gojo thought, his Six Eyes analyzing the energy flow. This 'Breath' is a form of breath control that mimics the elements. It's not chakra, but it bears a fundamental similarity to energy manipulation. And that 'demon's' regeneration is at a high level. These are definitely not ordinary curses.
The demon, frustrated by Tanjiro's tenacity, began to manifest its Demon Blood Art: bony tentacles sprouted from its back, attempting to impale the young hunter. Tanjiro, though skilled, was being outmatched by the demon's strength and speed.
"Damn!" Tanjiro exclaimed, narrowly dodging an attack that would have been fatal.
He could feel the exhaustion and despair, and at that moment, Gojo decided to intervene, not for the mission, but out of pure curiosity. He wanted to observe the power of these "demons" more closely.
Without Tanjiro or the demon noticing, Gojo moved a single finger. A small fragment of his Infinity, a bubble of slowed space, surrounded the demon. The demon, in the midst of its attack, abruptly stopped. For him, time had distorted, his movements becoming incredibly slow, as if he were moving through molasses.
Tanjiro, who had been expecting the final blow, blinked. The demon was frozen in midair.
"What... what's going on?" Tanjiro muttered, his gaze searching for the source of the anomaly.
Gojo Satoru appeared out of nowhere, right behind the demon, his figure casual and disinterested. His blindfold hid his eyes, but the sheer insolence of his presence was undeniable.
"My, my," Gojo said, his voice echoing in the sudden silence of the forest. "You seem to be having fun, kid. But this guy is a bit loud, don't you think?"
Tanjiro, with his extremely sensitive nose, detected a strange scent on Gojo. It wasn't demon energy; it was something different, something incomprehensibly vast and, oddly, clean—it didn't smell of fear.
The demon, now completely motionless within Gojo's Infinity, tried to scream, but the sound distorted and muffled.
"Now, let's take a closer look at this," Gojo touched the demon's body. "So, 'demons.' Regeneration. Blood Arts. Interesting. But their power source... it's a bit off-putting."
Gojo sensed the corrupted nature of the demonic energy, a twisted counterpart to the cursed energy of his own world.
"Who are you?! Get out of the way! It's a demon!" Tanjiro shouted, though he was puzzled by Gojo's control over the creature.
"Easy, kid. I'm in the middle of a little research," Gojo replied, not looking at Tanjiro. "And this guy... he's no match for it. He dissolves in sunlight, right? How inconvenient."
With a casual wave of his hand, Gojo activated a simplified form of his Hollow Purple. Not with the intention of annihilating, but purifying. A purple glow enveloped the demon. The creature screamed one last time, its form disintegrating into ash, not from the sun, but from the annihilation of its own energy.
Tanjiro watched, mouth agape, as the demon crumbled to dust before his eyes, not without the aid of his Nichirin blade. His mind could barely comprehend what he had just witnessed.
Gojo turned to look at Tanjiro, his blindfold still in place, but a sensation of piercing eyes. "So, you're a 'Demon Slayer'? And that sword helps you cut them down? How primitive."
Tanjiro recomposed himself, his sword ready. "I'm Tanjiro Kamado, a Demon Slayer! And you, who are you? You have a strange energy, and that... that's not a known Demon Blood Art!"
"Gojo Satoru," Gojo introduced himself with a smile. "Just some kind of passerby who stumbled into your world, and no, I'm not a demon. I'm just the strongest."
Gojo could sense the demon's trail, and even the presence of other demons in the distance, some more powerful than this one.
The system's mission for Gojo was to "investigate anomalies and stabilize the universe." And for Gojo, a universe filled with demons and slayers was a fascinating anomaly that promised a lot of fun.
The first step would be to understand how this place worked and how deep the "leaks" that had caused their arrival ran. And that meant, for now, interacting with the locals.
"So, Tanjiro Kamado," Gojo said in his usual tone.
"It seems you have a problem with demons. And I'm... curious. Maybe we could help each other, don't you think?"