Ever since Kaigaku was captured, Zenitsu hadn't been able to lift his spirits no matter what he did.
He had noticed everything Tanjiro and Inosuke were doing for him — even if they didn't say it aloud, he saw it, and he remembered it.
Deeply moved by their efforts, Zenitsu decided he couldn't keep running away anymore. As the only remaining successor of the Thunder Breathing style, he had a responsibility to carry on that legacy.
So, he told himself he'd mope around for just another day or two — and then pull himself together and return to training.
However, not long after falling asleep with that thought in mind, he was suddenly woken by voices echoing through the pitch-black room.
When Zenitsu opened his eyes, what he saw could only be described as a nightmare.
Two ghostly, pale-faced "female spirits" were hovering over him, staring down with cold, piercing eyes as if demanding his soul.
And strangely enough… those two "ghosts" looked suspiciously like Tanjiro and Inosuke. Their exaggerated makeup and clumsy, lumbering movements assaulted Zenitsu's already fragile nerves.
His golden hair stood on end like a startled cat, and under the combined shock to his body and mind, his eyes stung painfully — as if someone had sprayed pepper juice directly into them.
"Pigko! You're too close! The face powder's blowing right into Zenitsu's eyes!" Tanjiro scolded, pulling Inosuke back.
"It's dark! If I don't get close, how's Zentaro supposed to see us?" Inosuke protested — and immediately shoved his face even closer.
Sparks crackled across Zenitsu's body as lightning burst forth, cutting through the night. In the blink of an eye, he vanished from the room and appeared outside.
By the pond, Zenitsu frantically splashed water onto his eyes. "Gods… please! If this is a nightmare, just let me wake up already!" he prayed.
After several rinses, the burning finally eased, and he could see again — only to find Tanjiro and Inosuke standing right there, having followed him outside.
The two struck what they clearly thought were "seductive" poses, introducing themselves dramatically.
"I'm Tanko!" Tanjiro said, puffing his cheeks and poking at them with his fingertips.
"And I'm Inoko! Zentaro, have you already fallen hopelessly for my beauty?!" Inosuke flexed his biceps proudly, showing off his muscles.
Zenitsu glanced at Tanjiro. Then at Inosuke.
Then he dropped to his knees.
"Urrghhh—"
He gagged violently, nearly throwing up bile.
Tanjiro and Inosuke looked at each other in confusion.
"Tanko, what's wrong with him?"
Tanjiro guessed uncertainly, "Maybe… he's too moved?"
They started to approach, but Zenitsu recoiled in terror, scrambling backward on all fours.
"Stay away! Don't come any closer!"
After a chaotic struggle involving plenty of shouting and panic, Zenitsu finally calmed down enough to realize the two "female ghosts" really were Tanjiro and Inosuke.
"Why… why did you two make yourselves look like that? And what's with those ridiculous names — Tanko and Inoko?!" Zenitsu groaned, his voice thick with exasperation.
"We thought you'd like our look!" Tanjiro and Inosuke replied, feigning bashful tones.
Zenitsu's reddened eyes widened in outrage. "I like beautiful women — not demons!"
After a brief, awkward silence, Zenitsu suddenly murmured, "…Thanks."
Tanjiro and Inosuke blinked, confused by the sudden change in tone.
"I know you did all this just to cheer me up," Zenitsu continued softly. "I'm… really grateful to have friends like you."
Tanjiro waved his hands quickly. "You don't need to thank us, Zenitsu. It's what friends are for."
"Yeah!" Inosuke added proudly. "Zentaro, even though you're lazy, always complaining, and you lose your mind whenever you see a female—"
"Shut up, Inosuke!" Zenitsu's face turned bright red. "I'm not that bad!"
Zenitsu turned his gaze to the moon's reflection in the pond and began speaking quietly.
"I've always been my grandpa's most untalented disciple. When I first trained under him, I couldn't even perform a single Thunderclap and Flash."
"One day, when I was hiding in a tree to avoid training, lightning struck me by pure chance. My black hair turned this golden color from the strike — and somehow, after that day, I finally managed to pull off Thunderclap and Flash… barely."
"By that time, Kaigaku had already mastered every form except that one. I was so ashamed of myself."
"Kaigaku always hated me — said I was cowardly, weak, and a disgrace to Thunder Breathing. But still, I wanted him to acknowledge me. I was an orphan… and he and Ojiichan were the only family I had."
"When I went to Ojiichan in despair, he told me this: 'If you can only master one form, then perfect it. Polish it until you reach the ultimate limit — and then go even beyond that.'"
"I did my best to follow his words… but in the end, Kaigaku and I walked different paths."
All the frustration and sorrow Zenitsu had been bottling up for days poured out at once.
"Thank you, Tanjiro, Inosuke… for listening to me ramble like this."
Tanjiro placed both hands firmly on Zenitsu's shoulders. "Zenitsu, I'm sure your grandpa understands you — and that he's proud of you."
"That's right!" Inosuke added, punching his fist into his palm. "If your grandpa doesn't believe in you, I'll beat him up until he does!"
Tanjiro quickly clapped a hand over Inosuke's mouth. "Inosuke, please — don't."
"Pfft— hahahaha!" Zenitsu suddenly burst out laughing.
Tanjiro and Inosuke joined in, their laughter echoing together through the quiet night.
From that night on, Zenitsu truly regained his spirit — and threw himself back into training.
Just as Ubuyashiki had expected, the ordeal with Kaigaku had transformed Zenitsu. Now, he could draw out his full power even without slipping into his half-conscious state.
Half a month later, however, grim news arrived at Demon Slayer Corps headquarters.
Kaigaku had killed several Demon Slayers and escaped. Not only that, he had stolen centuries' worth of archives concerning the Ubuyashiki family.
A ten-man pursuit team was dispatched to capture him and bring him back alive.
But four days passed without any sign of Kaigaku — and then the entire pursuit team vanished.
When other Demon Slayers found the search site, all they discovered were ten frozen corpses, stiff and pale, bearing wounds consistent with Thunder Breathing techniques.
Upon closer examination, the victims' blood had completely solidified, and traces of deadly poison lingered — the unmistakable mar
k of a demon's Blood Demon Art.
The one who had taken Kaigaku away was clear beyond doubt.
Upper Moon Two — Doma.