"Is it too late to chase after Kamado Tanjirō?" Riku wondered aloud after having Kagerō, his cyber-wolf, mercilessly slaughter a nest of rats, earning him the title of "Hundred Rat Slayer."
Kamado Tanjirō was one of the few plot-relevant characters he knew in this world. The Kamado siblings had been recommended to seek out an old man named Urokodaki Sakonji, which screamed "mentor-seeking arc" straight out of a shonen anime. Last time, Riku had opted out of tagging along, worried his weak stats and glaring weaknesses would make sticking with the trouble-magnet protagonist a death sentence. He'd rather grind levels in the mountains, slaying beasts like a true RPG loner.
But things were different now. Sure, he hadn't become a "Ten-Mile Slope Sword God," but his full-body cybernetic reskin meant he no longer had to fear sunlight. He was ready to venture out and make some noise. His(gita, cybernetic body) might be a budget model, but it sounded pretty badass on paper. Immune to blades, guns, extreme cold, blistering heat, water, fire, and even lightning—plus, he could go invisible. Not too shabby.
"Let's take it one step at a time. If I could snag an oni, that'd be perfect," Riku decided, setting his sights on Sagiri Mountain as a loose destination.
He wasn't sure if Sagiri Mountain was a safe bet. What if it was one of those "protagonist faces early hardships" zones? If he dove in headfirst, Tanjirō might grab some plot-driven power-up and skip off, leaving Riku, the clueless side character, to get wrecked.
For now, he just wanted to hunt down an oni for some "basic company training." He needed to understand the whole oni deal—relying on trial and error wasn't cutting it.
"Where do oni even hang out?" Riku mused, chuckling at his own expertise as one himself. First off, they'd be where humans were. Too far from civilization, and you'd just be a starving oni.
"Thinking about it, cities probably have oni lurking in the shadows. Rural paths and highways, too—especially those must-travel routes where they can snatch a passing traveler for a quick meal."
Riku put himself in their shoes, and it made sense. Oni were patient predators, hiding in the wilderness, grabbing the occasional wayfarer to sate their hunger without drawing attention. It was safer than cities, where food was plentiful but the risk of exposure was higher—probably where the Demon Slayer Corps had their bases. Stronger oni could afford to haunt urban areas, but Riku wasn't ready to tangle with any big shots yet. One bite at a time. He'd start with a small fry to get the lay of the land.
Naturally, hunting oni meant going out at night. No demon was dumb enough to wander around in daylight, begging to get smoked.
Riku asked a passerby for directions to Sagiri Mountain. It wasn't too far, so he stuck to backroads, moving swiftly. His speed was a problem—too fast, and the optical camouflage hiding his horns would glitch out. Budget tech, what can you do?
He didn't stop until nightfall, having run all day. Aside from slicing up a few unlucky animals that crossed his path in the forest, he kept moving. Crossing mountains and valleys was no joke—what looked like "just a few peaks away" turned into a grueling trek. If he weren't an oni with near-endless stamina, this journey would've taken ages.
"Night's here. Finally feels safer," Riku said, relieved. As the sun set and darkness blanketed the world, that constant "death is one ray of sunlight away" dread vanished.
And with night came the oni hunting hour—their time to feast.
This time, Riku skipped the forest and stuck to a proper road, hoping to run into a reckless oni and save himself the trouble of tracking one down. He entered the mountains again, following a winding, treacherous path.
Even with his mask on, Riku's nose picked up the faint, tantalizing scent of humans. "People hiking through the mountains at night? That's just serving yourself up to an oni on a silver platter," he muttered.
It wasn't surprising. In this era, tales of oni were fading into old wives' tales. People didn't believe in them until it was too late. Maybe even Kamado Tanjirō didn't buy into those stories before his life got turned upside down.
Sniff, sniff.
Lost in thought, Riku caught a new scent—sharp, bloody, and unmistakably oni. One of his kind.
"Well, isn't this convenient? This demon hunter's been waiting for you," Riku said with a grin, his cybernetic eyes glinting in the dark. He'd been tailing a group of travelers, waiting for this exact moment.
As expected, an oni was hiding in these woods, preying on the group. The travelers—five in all, carrying heavy packs—were trudging through the night for who-knows-what reason. Even without oni in the equation, this rugged mountain path was dangerous at night. One wrong step could mean injury or death. Probably just folks scraping by, risking it all to feed their families. Life didn't give them much choice.
Too bad oni didn't care about their sob stories. To them, humans were just food—no matter how tragic their lives, it didn't add flavor.
Gulp.
In the thick darkness, the sound of swallowing saliva was jarringly loud. The travelers, quietly marching along, noticed the noise but assumed it was one of their own.
"Hungry already? Hang in there. There's a shrine up ahead where we can rest," the group's leader, an older man, said with a teasing chuckle.
"I can't wait! I'm starving!" came a reply—not from a companion, but from a feral oni bursting out of the woods.
The demon was a mess—wild hair, grotesque expression, built like a beast with strange patterns etched into its muscular frame. Drool dripped from its mouth, soaking its chest as it lunged at the leader with clawed hands.
Slash!
Riku, ready for the moment, darted in front of the traveler, katana flashing. With one clean strike, he lopped off the oni's head. The blade, fresh off the shelf, was razor-sharp and felt great in his hands.
"Demon Slayer?! Wait—no Nichirin Blade?!" the oni shrieked, its severed head hitting the ground. Its face twisted from terror to confusion. Still talking, it grabbed its head, retreated a few steps, and jammed it back onto its neck, twisting it into place.