At that moment, Kuwajima also noticed his flustered youngest disciple rushing out.
"Zenitsu, is your body alright now?"
Hiru, resting his chin on his hand, turned to look over and casually raised one hand in greeting. "Hah. This is the first time I've seen a human survive getting struck by lightning. You must be pretty sturdy—looks like you've been training properly."
However, as soon as Hiru finished speaking, Zenitsu's slightly dazed expression instantly twisted into sheer terror. Or rather, ever since he'd laid eyes on Hiru, fear had never left his face.
Zenitsu suddenly dashed forward, throwing himself in front of Kuwajima and Kaigaku. His entire body was taut with tension, his voice shaking uncontrollably.
"Who—who are you?! What are you doing here?!"
Hiru paused, then looked at Zenitsu with growing amusement.
"Oh? You noticed?"
In the next instant, Hiru vanished from Zenitsu's sight. That same terrifying voice, however, rang out right behind him.
"Well then, what should I do? Should I just get rid of all of you?"
Yet Zenitsu, who had been concentrating with everything he had to listen, heard another voice layered beneath it.
[How did this kid figure out I'm a demon? Another one with the Transparent World? No… he was already panicking before he even saw me. So it's sound-based recognition? That's impressive.]
Zenitsu froze once again, standing there blankly, not knowing how to react.
"You little brat!" Kuwajima slammed his cane down in annoyance. "Stop scaring my disciple!"
"Ah, sorry. His reaction was just too cute—I couldn't help myself."
"If you've got time to mess around, then hurry up and get out of Momoyama and go do your job!"
"I told you already. I'll leave after the craftsmen finish installing your prosthetic."
"Hmph!"
"So, old man, have you arranged lodging for me yet?"
"There's no lodging for you! Go work!"
"Well, I guess I'll have no choice but to sleep outdoors. Maybe I'll catch a chill and take sick leave."
"You little—!" Kuwajima's beard bristled upward again. In the end, he only snorted and turned toward the two stunned youths. "Kaigaku, Zenitsu, follow me!"
And just like that, Hiru successfully stayed.
Still, Kuwajima's two disciples ended up drawing his attention—because they kept finding opportunities to observe him from afar.
That said, their manners of observation were completely different.
Kaigaku watched him cautiously, almost furtively, as though afraid Hiru might hold a grudge. The moment their eyes met, he would bow quickly and disappear.
Zenitsu, on the other hand, watched him with pure vigilance—so much so that the instant Hiru made the slightest movement, Zenitsu would let out a filthy shriek and bolt.
Watching Zenitsu sprint away again the moment their eyes met, Hiru couldn't quite describe how he felt.
The kid looked fairly well-behaved at a glance, so how did he end up being such a mental case?
By comparison, Kaigaku's behavior might be unsightly, but at least his reactions were still within the realm of normal. This one, though…
"I need to think of something…" Hiru rubbed his chin thoughtfully. "If he's locating people through sound… then I should be able to move without making any noise, right? Mm. Let's give it a try."
...
Zenitsu finally stopped running, bent over and gasping for breath. He frantically scanned his surroundings, and only after confirming that Hiru hadn't chased him did he let out a shaky sigh and slump down against a tree.
He had been observing that Human Hashira for five days now.
Every single day, all he did was eat sweets and draw. He didn't look like a swordsman at all—he didn't even look like a demon.
What kind of demon spent all day basking in sunlight?
"All I can hear are thoughts about how good the sweets taste and how pretty the scenery is…" Zenitsu grabbed his hair, which had turned golden after being struck by lightning. "What does that demon even want? Even if I tell Grandpa, he won't believe me… What am I supposed to do?"
"So that's what you're worried about…"
Zenitsu whipped around, only to find Hiru standing behind him at some point without him noticing. He shot straight up into the air.
"Wahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh—!!"
"Tcs—" Taking a point-blank hit from that filthy high-pitched scream, Hiru reflexively covered his ears.
He watched Zenitsu bolt away like a startled rabbit, still shrieking, and sighed helplessly.
"If you keep running and screaming like that, I'll just go deal with those two."
Zenitsu froze mid-step. His mouth snapped shut, and the fear in his eyes as he stared at Hiru only intensified.
"Are you wondering why you can't hear my voice anymore?"
Hiru walked toward him slowly, stopping only when Zenitsu looked like he was about to faint from sheer terror.
"For demons, controlling our bodies is easy. As long as all my organs stay completely still, I'm basically just a moving corpse. You can't hear a dead person's sounds, can you?"
Zenitsu pressed himself tightly against the tree behind him. His voice trembled, but his expression was unusually resolute.
"Y-you… what exactly do you want?"
"Shouldn't I be asking you that?" Hiru crossed his arms and sighed. "Why have you been following me around? Don't tell me you like men."
"Of course not!" Zenitsu exploded like a cat whose tail had been stepped on. "What's so great about stiff, hard men?! Soft, sweet girls are the best! Just catching a whiff of their fragrance when they pass by, or getting to stare at them—that alone is bliss!"
"…This might be a bit rude," Hiru took a step back, covering the lower half of his face with one hand, his expression complicated, "but you kind of disgust me."
"What do you know?!" Zenitsu was about to argue back when that terrifying sound appeared again. Instantly, he went silent, like a chicken being grabbed by the throat.
"In any case, I have absolutely no interest in discussing how wonderful girls are with you," Hiru lifted his hand and once again halted the movement of his internal organs. "Talking about romance with a kid a few hundred years younger than me would just make me look stupid."
Zenitsu slowly recovered and lifted his head to look at Hiru.
"Then… what do you want? Are you going to turn me into a demon?"
"Give me a break." Hiru folded his arms, his gaze filled with disdain. "Just imagining you as my descendant makes me feel secondhand embarrassment, okay?"
Zenitsu: …
"I'm here to answer your questions," Hiru said flatly. "Ask what you want, then stay away from me—just like your senior. Do you have any idea how unbearable it is to draw while being stared at by a kid who starts screaming the moment you look at him?"
"You… you're really not a demon who eats people?" Zenitsu swallowed hard. "Then how did you join the Demon Slayer Corps? Why did you join?"
"I don't eat people. I survive by regularly consuming animal blood. As for why I'm in the Demon Slayer Corps…"
Hiru clicked his tongue irritably.
"Good question. I'd like to know myself why I ended up working for humans here. I only wanted to learn woodcarving, and somehow it turned into all this trouble… What's with that look?"
"You're a demon who overcame sunlight, and you sold yourself to the Demon Slayer Corps just to learn woodcarving…"
Zenitsu covered his mouth.
"That's… really lame."
Hiru: "…Do you believe I won't actually kill you?"
Zenitsu immediately bowed deeply. "I'm sorry."
"Anything else you want to ask?"
"Um… when I told Grandpa about you, why didn't he believe me? What did you do?"
"Ah, that."
Hiru stroked his chin.
"Do you think a demon slayer who's spent his entire life killing demons at night would believe there's a demon who overcame sunlight and doesn't eat people? I can barely believe it myself."
Zenitsu: …
[This demon… something's not right.]