A fang-dart struck Nezuko's back, muffled by her bamboo gag. She grunted in pain.
"Nezuko!" Tanjiro's voice cracked with panic.
Thankfully, Nezuko's demonic healing sealed the wound instantly, though the embedded fang slowed her down, pain lingering. With a fierce cry, she clashed again with the fang-demon, their claws tearing through the air.
Tanjiro, watching, saw Nezuko's speed falter, the fight tipping against her. "Damn it!" He slammed his fist into the ground, seething at his weakness—too powerless to protect his sister, who was injured because of him. "Damn it! I'm useless! I'll fight you to the end!"
Fueled by rage, Tanjiro grabbed his axe with his uninjured arm and charged. The demon kicked him away effortlessly. As it lunged to devour him, Nezuko, enraged, barreled into it, standing protectively before her brother, claws bared, growling like a cornered beast.
The fang-demon scoffed. "What are you two? You're a demon—why not eat him? Why protect a human?"
Tanjiro, gasping, gripped his axe. "Nezuko would never eat me! She's my sister—my most precious family!"
"Tch!" The demon sneered. "I'll rip your family apart, then eat you!"
It charged, clashing with Nezuko again. Tanjiro struggled to rise, but broken ribs left him useless. Nezuko was losing ground. Despair sank in—he was dragging her down. She was in danger because of him.
Glancing around, he saw no help, no hope. Trapped in this dire moment, a grim thought struck: demons eat humans, not other demons. If he let this demon take him, would it spare Nezuko? But if he died, how would she survive?
In the original story, Tanjiro never sank to such despair, even in the darkest moments. This wretched butterfly effect had pushed him to the edge.
Nezuko, new to her demonic form, was no match. The fang-demon sent her crashing into a tree with a pained groan, sliding to the ground.
"Nezuko!" Tanjiro screamed, madness in his voice.
At that moment, Horitake arrived. "Thunder Breathing, First Form: Thunderclap and Flash!"
Lightning crackled as he became a blur, slashing with lethal precision. The fang-demon turned, too late, eyes wide with terror as purple lightning closed in. Slash! Its head fell, severed clean.
Nezuko's grape-like eyes locked onto the stranger, unblinking. Tanjiro gaped, relief flooding him, collapsing in the aftermath. Nezuko, sensing no threat, scurried to his side, worry in her gaze.
Tanjiro exhaled, hugging her tightly, tears streaming. "Nezuko, you're okay… I was so scared…"
Nezuko, hesitant, returned the embrace, eyes soft and innocent.
Horitake, sheathing his blade, sighed in relief, moved by the siblings' bond. The demon's corpse, beheaded by a Nichirin Blade, dissolved into ash.
The siblings, recovering, turned to their savior. Tanjiro rushed forward, dropping into a deep bow, forehead smacking the ground. "Arigatou! Thank you so much for saving us!"
Horitake, unused to such gestures despite years in this world, pulled him up. "No need, kid, no need."
"It's necessary, senpai!" Tanjiro insisted, nearly bowing again. "Without you, we'd be dead in this wilderness! We owe you everything!"
Tanjiro's gratitude was boundless; he'd likely agree to anything Horitake asked. Horitake, holding the stubborn boy back, chuckled. No way he'd accept such deference from his future brother-in-law.
After calming Tanjiro's fervor, they spoke more evenly. Horitake couldn't admit he came specifically for them, so he improvised. "No big deal. I've been tracking this demon for a while. You two were unlucky—cloudy skies, no sun, it got bold and attacked in daylight."
Realizing he sounded too casual, he added a cover. "Wait, your sister's a demon!" Drawing his Nichirin Blade, he feigned menace toward Nezuko. "Guess I'll have to end her!"
Tanjiro, panicked, grabbed Horitake, echoing his plea to Giyu from the day before. "Senpai, stop! Nezuko's a demon, but she doesn't eat people! She won't hurt anyone! I'll make sure of it! She's a good demon!"
Horitake played skeptical, struggling against Tanjiro's grip. "What are you talking about? A good demon? No such thing! I know she's your sister, but demons must be slain!"
"No, senpai, it's true! She didn't attack you or me—she protected me! You saw it!"
"Well, sure, but…" Horitake kept up the act, tussling lightly.
Nezuko, wide-eyed and bewildered, watched her brother grapple with the strange swordsman, her expression adorably confused.