Upon hearing that Kaigaku had been taken away by a demon, Zenitsu's face was clouded with sorrow.
Tanjiro and Inosuke, too, were deeply worried — afraid that Zenitsu might once again lose his will to fight.
"Are you okay, Zenitsu?" Tanjiro asked with concern.
Zenitsu shook his head. "I'm fine… It's not myself I'm worried about — it's Ojiichan."
His brows were furrowed with anxiety. "Kaigaku… that guy will do anything to gain power. If Ojiichan finds out he's become a demon, I'm afraid the shock will crush him."
"Then why don't we go see your grandpa tonight?" Inosuke suggested straightforwardly.
Zenitsu nodded without hesitation. Right now, he wanted nothing more than to see Jigoro Kuwajima.
The three of them went to Yosuke's room and explained their wish to travel to Mt. Momoyama to visit Jigoro.
Seeing the anxious look on Zenitsu's face, Yosuke pondered for a moment before saying, "It's almost nightfall. Very well — I'll take you there myself. That way, we'll reach him faster."
As soon as the sun dipped below the horizon, Yosuke carried the three boys through the night sky toward Momoyama.
When they arrived, Zenitsu couldn't wait another second. He bolted up the mountain trail toward the small wooden cabin at the summit.
Throwing open the door, Zenitsu found Jigoro Kuwajima sitting motionless at a table, lost in thought.
"Ojiichannn! Are you all right?!" Zenitsu cried, throwing himself into Jigoro's arms.
Jigoro quickly wiped away the tears welling in his eyes and gently patted Zenitsu's head. "Zenitsu… you're back. Ojiichan's fine."
When Jigoro noticed Yosuke standing by the door, he rose to his feet. "Ah, Yosuke-san. You came too."
Yosuke looked at the old man's head of snow-white hair and sighed softly. "You've grown old, Jigoro."
Jigoro gave a faint smile tinged with bitterness. "Yes… I've grown old — and blind to my own faults. I took in a disciple who turned against everything I taught. My sins are unforgivable…"
Zenitsu immediately objected, shaking his head desperately. "No, Ojiichan! It's not your fault — it's Kaigaku's fault!"
Yosuke turned to Zenitsu and said gently, "Zenitsu, let me speak with your grandfather alone for a bit."
Zenitsu nodded reluctantly and stepped outside with Tanjiro and Inosuke.
Inside, Jigoro brewed a pot of tea made from peach blossoms. The two men sat together on the floor.
After taking a sip, Yosuke spoke. "You still have Zenitsu — a fine disciple, isn't he?"
A small smile formed on Jigoro's face. "Yes… Zenitsu has grown into a Demon Slayer who can stand on his own. He'll go much farther than his useless old master ever could. And I owe you thanks, Yosuke-san. Despite our past misunderstandings, you still helped guide him."
Yosuke shook his head. "There's no need to thank me. Zenitsu's a boy I truly care for as well. …What do you plan to do next?"
"Someone must answer for Kaigaku's sins," Jigoro said solemnly. "As his master, that responsibility is mine."
Sensing the grim resolve behind his words, Yosuke frowned. "Are you really planning to do this? You know full well you have more than one student. If you die… the one who will suffer most is Zenitsu."
Jigoro closed his eyes. "To have raised a pupil like Zenitsu — I can die without regret. But if I don't atone, then those Demon Slayers killed by Thunder Breathing will never rest in peace."
Outside, Zenitsu, with his sharp hearing, caught every word.
Panicking, he burst back into the cabin, tears streaming down his face. "Ojiichan! No! You can't die! I don't want you to die!"
Seeing his grandson's desperate sobbing, Jigoro's own tears began to flow.
"It's all my fault!" Zenitsu cried. "Kaigaku became like this because of me! If someone has to die, it should be me!"
Smack!
Jigoro's hand struck Zenitsu's cheek. "Don't you dare say such a thing!"
But Zenitsu didn't flinch. Instead, he grabbed onto Jigoro's sleeve tightly. "I still haven't repaid your kindness, Ojiichan. Please… don't die."
Jigoro's heart broke as he embraced the boy tightly.
Watching the two weep together, Yosuke offered a compromise. "How about this — let Zenitsu be the one to pursue Kaigaku. If Kaigaku has truly become a demon, then Zenitsu will be the one to end him. They shared the same master — it's fitting. If Zenitsu fails, then, Jigoro… the choice of atonement will be yours to make."
Jigoro hesitated, looking at Zenitsu's tear-streaked face. Then, with great difficulty, he nodded.
When Jigoro abandoned his resolve to commit seppuku, Zenitsu broke down crying — this time from relief.
Outside the hut, Tanjiro and Inosuke smiled faintly, happy for their friend.
Yosuke soon prepared to depart with the three of them. Zenitsu, still in tears, waved goodbye to his grandfather.
Jigoro watched them go, murmuring softly to himself, "Zenitsu… do your best. And live on, my boy."
Meanwhile, Kaigaku had followed Doma to the newly established Eternal Paradise Faith.
He now knelt before Doma, his voice trembling with eagerness. "Please… grant me power!"
Doma smiled — a perfect, empty smile devoid of warmth. "Since you've brought me what I wanted, I'll grant your wish. I'll give you my blood. But remember — life is a precious thing. You must cherish it, won't you?"
He reached out his pale hand and let his blood drip into Kaigaku's throat. "Do you have what it takes to become one of the Twelve Kizuki like me — perhaps even reach the Upper Moons?"
Kaigaku's eyes burned with greed. "Thank you, Doma-sama! I swear, I'll become one of the Upper Moons!"
He drank hungrily, feeling the demonic power surging through his body.
"Zenitsu Agatsuma… next time we meet, I'll kill you!"
Back at the Butterfly Mansion, the Butterfly Sisters and Tamayo brought good news to Yosuke.
The demon who had been captured — Mando — had finally been freed from Muzan Kibutsuji's curse.
Yosuke rushed to the laboratory at once.
Mandō had regained consciousness, but his eyes were empty, unseeing. No matter what anyone said to him, there was no response.
"Though he's been freed from Muzan's curse," Tamayo explained, "his reason hasn't returned. It's as if he had already lost his mind before he ever became a demon."
No matter what medicines they tried, Mandō remained unresponsive — leaving Tamayo and the Butterfly Sisters at a loss.
"Let me try," Yosuke said. "Now that Muzan's curse is gone, if I inject my own blood, I should be able to peer into his memories."
He pressed his fingertip against Mandō's temple and began infusing his blood.
To his surprise, the process went smoothly. The demon blood inside Mandō didn't resist.
Yosuke closed his eyes and began searching through Mandō's memories.
Chaos.
Utter, formless chaos.
His memories were a tangled mess — like a ball of knotted thread, drenched in blood and death.