Demon Slayer: Dragon Hashira#17/19: Speculation & Kaidō the Matchmaker, Obanai Iguro's Past, Upper Rank Two—Doma, Fighting Doma.

Demon Slayer Corps Headquarters

After greeting the other Hashira, Kaidō made his way to the Ubuyashiki estate, hoping to speak with Kagaya.

Outside the estate entrance, he spotted a Kasugai Crow—likely Kagaya's personal messenger. Kaidō explained his purpose, and the crow flew off to announce his arrival.

A few moments later...

Creak.

"Kaidō-sama, Father has asked me to escort you. Please follow me." Kanata Ubuyashiki opened the door with her usual emotionless courtesy.

Following Kanata into the courtyard, Kaidō found Kagaya seated formally on a tatami mat alongside his wife, Amane Ubuyashiki. He took a seat across from them.

"My beloved child, welcome back." Kagaya's voice carried its characteristic warmth. "I've heard about your work this past month. You not only eliminated a Lower Rank demon but also cleared your entire patrol zone of threats. The people there can finally live without fear. I'm truly proud of you."

That voice really does put you at ease, Kaidō thought.

"It's my duty as a demon slayer. Nothing more than what's expected."

"The crow mentioned you had an urgent matter to discuss. Is something troubling you? You can always confide in me."

"Actually, it's about your curse, Master." Kaidō made a show of reaching into his pocket while actually pulling an Enhanced Longevity Pill from his system inventory. "If you're willing to trust me, please take this."

Kagaya accepted the pill without hesitation and swallowed it immediately.

"You're not going to ask what it is first?"

"I trust my children would never harm me."

Kaidō felt genuine admiration for Kagaya—a man with such a magnanimous heart and complete faith in his subordinates.

Then something incredible happened.

The curse marks on Kagaya's face began to recede. His skin cleared, vitality returning to his features. When the transformation finished, Kagaya looked... honestly pretty handsome.

"What is this?" Kagaya's shock was evident despite his usual composure.

"A family heirloom—an Enhanced Longevity Pill. It can't eliminate your curse entirely, but it significantly weakens and delays its progression. And I imagine you'd like to witness Muzan Kibutsuji's downfall with your own eyes, wouldn't you?"

Kagaya looked at his wife and children, then—to Kaidō's horror—all four of them prostrated themselves in gratitude.

"SUCH A PRECIOUS TREASURE... THE UBUYASHIKI FAMILY WILL NEVER FORGET THIS KINDNESS!"

"Master, please!" Kaidō quickly helped him up. "There's no need for this. You're giving me way too much credit."

"THANK YOU FOR SAVING FATHER!" Kanata and Hinaki bowed deeply.

...

After talking with Kagaya for a while longer, Kaidō returned to his estate to rest and strategize about the timeline ahead.

He lay on his bed, thoughts racing.

'Six or seven months until Tanjiro's family gets attacked and Nezuko turns into a demon. But should I even interfere? If I stop it, Nezuko won't become a demon—but we need her Blood Demon Art later. The Infinity Train arc, for example.'

'What if my interference creates a butterfly effect? Muzan might go into hiding for another century. Or worse—everything could accelerate, the entire Corps could be wiped out, and Sun Breathing might be lost forever.'

'But if I don't interfere, Tanjiro loses his family. Nezuko becomes a demon. Though... demon Nezuko does help everyone tremendously in the later arcs.'

Then there's the Infinity Train. Rengoku fights Akaza, gets his abdomen pierced. That's when his sword grip strength increased and his blade started glowing faintly—the first signs of a Crimson Blade manifesting.

"Ugh, why am I overthinking this? Focus on what I can control: keeping the Hashira alive and helping Yushiro save Tamayo during the final battle in the Infinity Castle."

"I can't make any promises about Tanjiro's situation, but I should at least visit. He'll be my junior brother eventually. Plus, little Nezuko is adorable."

A mischievous grin spread across his face.

"More importantly... I should try my hand at matchmaking. Let's see if I can push Obanai and Mitsuri together. Those two are perfect for each other. Hehehehe!"

The image of them as a couple made Kaidō break into what could only be described as a scheming auntie smile before he passed out from exhaustion.

...

Noon the Next Day

A Kakushi member arrived at Kaidō's estate. "Kaidō-sama, I've brought what you requested!"

The Kakushi handed over a large bag filled with sakura mochi.

That morning, after washing up, Kaidō had asked a Kakushi to buy the sweets on his behalf. His master plan to unite Obanai and Mitsuri was officially underway—starting with Mitsuri's weakness for food.

"Perfect. Thanks for your help!"

"Not at all—it's my duty!"

'Now the real work begins. Obanai better treat me to a fancy dinner after this succeeds. Hehehehe!'

...

Somewhere in the middle of a mission, Obanai Iguro sneezed suddenly. 'Strange. Who's thinking about me?'

...

"Mitsuri-nee! There you are!"

"Oh! Kaidō-kun! Were you looking for me?" Mitsuri's face lit up immediately. 'He came to find me! And he called me 'nee-san' again! I'm so happy! He's so cute—I really want to hug him!'

"Yep! Obanai-san asked me to give you this." Kaidō held out the bag.

"Eh? Obanai asked you to give this to me? What is it? WOW! Sakura mochi! Please thank Obanai for me! Kaidō-kun, let's eat together!"

"Can't—I've got a mission!" Kaidō used the excuse to make a strategic retreat.

"Oh, a mission! Well, good luck! You're working so hard. Next time you're free, let me treat you to a meal as thanks!"

"Deal! I definitely won't say no to free food! Hehe!"

...

Two Months Later

For two solid months, Kaidō had been delivering food to Mitsuri—sakura mochi, dango, various sweets—always claiming they were gifts from Obanai.

Every time Mitsuri saw Obanai afterward, she'd thank him profusely. Obanai had no idea what was happening, but seeing Mitsuri smile made him too happy to question it.

Until one day...

"Mitsuri-nee, I've got a mission. Oh, and Obanai-san wanted you to have these mochi dumplings."

"Huh? Why does Obanai always have you deliver things instead of giving them to me himself?"

"Probably just shy! Anyway, gotta go—bye, Mitsuri-nee!"

"Oh, okay... bye."

Hidden in a nearby tree, Obanai had witnessed the entire exchange.

"So it was you doing all this? And you've been saying the gifts were from me?" He immediately took a shortcut to intercept Kaidō.

...

"Kaidō! Stop right there! I need to talk to you!"

Kaidō turned to see Obanai approaching rapidly. "Oh, Obanai-san! What's up?"

"Why did you do it?"

"Do what? I have no idea what you're talking about."

"Don't play dumb. Why have you been giving Mitsuri presents and claiming they're from me?"

"Before I answer that, let me ask you something: Do you like Mitsuri? Be honest."

"I... I..."

"You like her, don't you? You're just afraid of being rejected."

"How did you—"

"How did I know? It's obvious. You light up every time you see her. When you're together, you wish time would slow down. You even gave her those striped stockings. Am I wrong, Obanai?"

The accuracy of Kaidō's observations left Obanai speechless. He lowered his head, wrestling with thoughts he couldn't voice.

"Obanai." Kaidō's tone shifted, becoming more serious. He dropped the honorific entirely. "One simple question: Do you love Kanroji Mitsuri?"

After a long silence, Obanai seemed to reach a decision. His hands moved to the bandages wrapped around his face. Slowly, he unwound them.

The scars were revealed—his mouth split grotesquely from ear to ear.

He looked up at Kaidō. "Will you listen to my story?"

"Yeah."

They sat down beneath a tree. And Obanai Iguro began to speak about his past.

...

<><><><><><><><>

Obanai Iguro's past was nothing short of tragic.

He'd been born into a family that had only produced daughters for generations—a clan of thieves who stole property and wealth from others to survive. Greedy, stubborn, vain. The family hadn't seen a male heir in three hundred seventy years.

From the moment of his birth, Obanai's heterochromatic eyes marked him as different. They locked him in a windowless cell and brought him lavish meals every day—food that made him nauseous rather than hungry.

Every night, he heard something massive slithering across the floor outside. He could feel a viscous, suffocating gaze watching him through the darkness.

He was twelve years old when they finally dragged him from his cell.

Face to face with a demon—a woman with a serpent's lower body—Obanai learned the truth. For centuries, his family had survived by offering their children as living sacrifices to this snake demon who murdered and stole on their behalf. The demon preferred eating infants.

But Obanai was special. A rare male child with unusual eyes. The demon found him interesting and decided to fatten him up before devouring him.

To make him match her appearance, the snake demon ordered his family to carve his mouth open from ear to ear.

Thrown back into his cell, Obanai spent every waking moment planning his escape. He stole a hairpin and spent months slowly carving through the wooden bars. The only creature he could trust was Kaburamaru—a small white snake who'd wandered into his cell by accident.

Every day, Obanai lived in constant fear of discovery.

Finally, he escaped.

The snake demon caught up to him just as he encountered the Flame Hashira of that era.

Enraged by his escape, the demon slaughtered Obanai's entire clan. The only survivor—his cousin—spat venom at him instead of gratitude:

"This is all your fault! Everyone's so upset because you ran away! You should've just let her eat you!"

She blamed him for everyone's deaths. He was the sacrifice—he should have accepted his fate quietly.

Those words shattered something inside Obanai Iguro. He began to believe he was trash, born from a family of trash. Unable to direct his anguish anywhere else, he poured all that rage and self-loathing into killing demons.

Only when saving others by slaying demons did he feel any semblance of redemption.

But the past refused to let him go. It dragged behind him like chains, weighing down every step. The only way to achieve purification, he believed, was to die after killing Muzan.

With a mindset bordering on suicidal, Obanai had thrown himself into the fight against demons without looking back.

...

After finishing his story, Obanai looked at Kaidō. "Someone like me... do I even deserve to be with her?"

Kaidō took a breath before responding. "Obanai, everyone has a different past. You can't tear yourself down because of where you came from. Your family's crimes aren't your crimes."

He leaned forward. "Think about it—what would've happened if you hadn't escaped? You'd be dead. And your family would've kept partnering with that snake demon, killing more people, destroying more families. How many would've died? How many children would've lost their parents?"

Kaidō's voice grew firm. "That family deserved what they got. But you're different. Because you made that choice, you saved countless lives from suffering at their hands. So forget this 'deserve' nonsense. If you love someone and they love you back, they won't care about your past."

"But I—"

"No 'buts,' Obanai. If you really love Mitsuri, tell her. Even if she rejects you, at least you won't spend the rest of your life wondering 'what if.'"

Silence stretched between them. Finally, Obanai spoke.

"I understand. Thank you, Kaidō."

...

The Next Day

Kaidō was training in his courtyard when he spotted Hotaru Haganezuka approaching in the distance.

"Haganezuka-san! What brings you here?"

"Hmph! I'm here to engrave your sword, obviously!"

"Engrave what?"

"You IDIOT! Every Hashira's Nichirin blade gets the inscription 'Destroyer of Demons' engraved on it! Obviously!" Haganezuka jabbed his finger repeatedly into Kaidō's forehead with each word.

"Okay, okay! I get it! Here—it's all yours. Thanks for doing this!"

Haganezuka accepted the greatsword and examined it carefully. "Well, well! You've kept the weapon I forged in pristine condition—not a single chip or crack. Excellent! Hahaha!"

"So, uh, how long will the engraving take? I have a mission tomorrow."

"Won't take long. Half a day at most."

"Perfect. I appreciate it!"

...

After Haganezuka finished the engraving, Kaidō presented him with a box of mitarashi dango as thanks. The swordsmith's mood immediately brightened.

Before leaving, Haganezuka issued a stern warning: "Don't you DARE damage this blade, or I'll never forgive you!" Then he departed happily, dango in hand.

Watching him go, Kaidō chuckled. "Now I understand what Tanjiro went through. Still... we're lucky to have the swordsmiths. Without them, fighting demons would be nearly impossible."

He returned to his training.

...

Six Months Later

Kaidō was racing toward Tanjiro Kamado's home in the mountains.

"If my timeline estimate is right, this should be around when the story begins. Hope I'm not too late."

He knew the general plot, but the exact timeline? That was fuzzy at best. He could only make educated guesses.

"There—that's the mountain." He increased his speed, bounding up the snowy slope.

...

On the Mountain

A boy ran desperately down the snow-covered path, carrying a bloodied girl on his back.

"Why? Why did this happen?! Nezuko, hang on! I won't let you die! I'll save you—I promise I'll save you!" Tanjiro's voice cracked with desperation.

"Ah!"

His foot slipped. He tumbled forward, rolling down the slope.

THUD.

"Saved... the snow saved me. Even though the snow is what made me fall in the first place..."

"Nezuko! Are you okay?!" He looked toward where his sister had landed. She was standing—alive.

Relief flooded through him. He scrambled over to embrace her.

Then he saw her eyes.

"Nezuko... no. A demon?! Nezuko turned into a demon?!"

...

"Faster. Come on, faster—please let me make it in time... Hm?" A loud crash echoed from somewhere ahead. "That direction... that's where... Giyu!"

Kaidō changed course immediately.

When he arrived, Giyu Tomioka had already placed a bamboo muzzle over Nezuko's mouth and laid her beside the unconscious Tanjiro.

"Senpai."

"Mm." Giyu acknowledged him with a nod.

"I'll take it from here."

"Fine. Make sure you write to Master Urokodaki about this."

"Will do."

Giyu departed without another word.

Kaidō sighed heavily. "Well, this is just great. Still got here too late. Should've rewatched the anime a few more times when I had the chance—then I'd have the timeline memorized. Ugh."

...

"Nezuko! Thank god you're okay! I was so worried!"

"You're awake, Tanjiro."

"You're... that scent. I know that scent." Tanjiro stared at the masked figure. "It's so familiar. Have we met before?"

"What, you forgot me already?" Kaidō removed his fox mask.

"Kaidō-san! It's you! I'm so glad to see you!" Tanjiro's expression crumbled. "Kaidō-san, my mother—someone killed her! And my brothers and sisters, they're all... and Nezuko, she... she..."

Tears streamed down his face.

"I'm so sorry for your loss, Tanjiro." Kaidō's voice was gentle. "Let's give your family a proper burial first. As for Nezuko—I believe there's a way to turn her back into a human."

"Thank you, Kaidō-san. Thank you so much."

...

After helping Tanjiro bury his family, Kaidō gave him instructions.

"Go to Mount Sagiri. Find a man named Sakonji Urokodaki. Tell him Giyu Tomioka and Ryūjin Kaidō sent you. He'll teach you what you need to know."

"What about you, Kaidō-san?"

"I've got other things to handle. The path ahead—you'll have to walk it yourself." Kaidō placed a hand on Tanjiro's shoulder. "Your family took me in once. Treated me like I was one of you. If you're family, then Nezuko's my little sister too. I'll help find a way to turn her back into a human."

"Thank you, Kaidō-san! I promise I'll do exactly as you said!"

<><><><><><><><>

"Today's definitely not going to be peaceful." After that philosophical observation, Kaidō prepared to head back to Corps Headquarters.

Passing through a village after nightfall, an uneasy feeling gnawed at his gut.

"What's going on? Why do I feel so on edge? Is something about to happen?"

The closer he got to the village, the stronger the sensation became—like standing in a pitch-black room, surrounded by invisible threats.

"Something's wrong. It's too quiet. Just like last time. Something's definitely going down."

"Dragon Breathing, First Form: Dragon's Breath."

The unnatural silence forced Kaidō onto high alert. He activated Dragon's Breath immediately, readying himself for whatever came next.

"Kuroha! Scout from above!"

"CAW CAW! Got it!" The crow took flight, circling overhead.

"Please let this just be paranoia."

A voice rang out from behind him—cheerful, dissonant with the oppressive atmosphere.

"Hello there, beautiful young lady! It's awfully dangerous to be out this late. Would you like some help?"

Kaidō reacted instantly, leaping sideways to create distance. When he got a clear look at the speaker, his entire body tensed. Cold sweat trickled down his spine.

White-oak hair. Rainbow-colored eyes. The top of his head looked like someone had dumped blood over it. An easygoing smile plastered across his face, voice smooth and gentle. The kanji for Upper Rank Two carved into both eyes.

Kaidō knew exactly who this was.

"Upper Rank Two—Doma."

"Oh my! Someone actually knows my name! How surprising!" Doma's smile widened, as if being recognized was the most shocking thing in the world.

Even as a human, Doma had been incapable of understanding emotions. He'd lived his entire childhood without experiencing joy, anger, sorrow, or happiness. Love and hate were foreign concepts. Unlike other demons whose personalities warped after transformation, Doma's psyche had been twisted from birth.

Raised as a vessel for people to unload their suffering onto, he'd developed a disturbing philosophy: death was salvation for humanity.

As a demon, he particularly enjoyed devouring young women, calling it "salvation" and claiming those he ate would achieve eternal life through him. He believed women possessed superior nutrients due to their ability to bear children, and couldn't understand why Akaza refused to eat females.

He didn't believe in gods. Possessed a childish, playful streak. Would deliberately hold back in combat—partly to gather intelligence on Breathing Styles, partly to toy with opponents and gauge their strength.

"Oh? You're actually a boy? How disappointing! If you were a girl, you could've achieved eternal life with me! You're a Demon Slayer, aren't you? Hey, hey—tell me your name..." Doma kept chattering, growing more enthusiastic with every word.

'I can't believe I ran into an Upper Rank. Just his presence alone is suffocating. Doma's no pushover—his attacks carry ice poison. Gotta be careful. Hope Kuroha can alert the other Hashira in time!'

Kaidō lowered his fox mask over his face and pulled his greatsword from the system inventory.

"Whoa! What kind of trick was that?! How fascinating! Can you teach me how to do it?" Doma's curiosity was almost childlike.

"Dragon Breathing, Fifth Form: Violent Tempest!"

After two Body Reinforcement enhancements, Kaidō could now unleash nearly two hundred blade projections. The barrage shot toward Doma.

"Blood Demon Art: Crystalline Divine Child!"

Five ice puppets materialized—miniature replicas of Doma himself. Despite their small size, they possessed formidable combat ability and could even use Blood Demon Arts with power matching the original.

CRASH! BANG! BOOM!

The two hundred blade projections destroyed three puppets. The remaining two charged forward.

"Blood Demon Art: Scattering Lotuses!"

The ice puppets swung their fans, scattering countless tiny ice flowers. Each petal was razor-sharp, cutting through the air toward Kaidō.

"Dragon Breathing, Fourth Form: Coiling Dragon!"

Recognizing the danger, Kaidō immediately switched to defense. He gripped his sword handle with both hands, planting the blade's tip into the ground. A translucent barrier formed around him, blocking the puppets' assault.

THUD THUD THUD!

"Damn—too strong!" The relentless barrage shattered his defense. The two ice puppets lunged forward.

"You think I'm easy prey?! Dragon Breathing, Third Form: Divine Dragon's Tail!"

A massive fan-shaped wave of force swept forward, obliterating the last two puppets. The residual energy continued toward Doma himself.

Doma's smile never faltered. He swung his iron fans casually, dispersing the attack.

CLANG!

"Wow, impressive! You can hit me from that distance? You really are different. You're a Hashira, aren't you? Though you look so young!"

His grin widened. "But you're quite interesting. I think I'll play with you for a while!"

"Blood Demon Art: Creeping Lotuses!"

Multiple ice vines covered in frozen lotus flowers erupted from the ground, attempting to bind Kaidō.

"Dragon Breathing, Fifth Form: Violent Tempest!"

Kaidō used the Fifth Form again to counter Doma's technique. But he understood—Doma was just toying with him, testing his abilities. If Doma got serious, he'd already be dead.

CRASH!

Though the ice vines shattered, fragments of ice sliced into his exposed legs and hands. A thin layer of frost immediately formed on his skin.

"Oh dear, my ice is poisonous, you know. I wonder how long you can last?"

I need to get close to decapitate him. But I have to watch out for his ice mist—it's lethal. Kanae Kocho inhaled it and her lungs necrotized. If she hadn't lasted until dawn, there wouldn't even have been a body left.

"Dragon Breathing, Ninth Form: Cyclone Pierce!"

Kaidō launched himself forward in a high-speed drilling motion. Doma couldn't react in time. He barely managed to twist his body, but the technique still severed one of his arms.

"I can do this. But it's not enough—I have to decapitate him!"

"Dragon Breathing, Second Form: Dragon Claw!"

After the pierce, Kaidō spun and leapt into the air, bringing his blade down in a devastating overhead slash aimed at Doma's neck.

After losing an arm, Doma looked momentarily surprised. He turned, searching for his opponent.

"Huh? Where'd he— Wait, above!"

A vicious strike descended from overhead, aimed directly at his face.

"Blood Demon Art: Withering Frozen Garden!"

Doma swung his fans in a nine-strike combo infused with frost, neutralizing Kaidō's attack and sending him flying backward.

"Guh!" Kaidō hit the ground hard, coughing up blood that dripped from beneath his mask.

"Damn it... still not enough? Am I really going to die here? No! I still have things I need to do! I have to go home and see my mother and my sister! I can't die here—I refuse to give up!"

Using his greatsword as support, Kaidō forced himself upright.

"Mark—activate!"

The dragon-shaped mark on his forehead blazed blood-red beneath his mask. Power flooded through his body—strength, speed, reflexes all amplified dramatically.

Doma felt the shift in Kaidō's aura. A strange sound echoed in his ears—something he couldn't identify. For the first time, Doma felt a flicker of fear. His playful demeanor vanished. Time to get serious.

...

Meanwhile

Kuroha raced toward the nearest Hashira at maximum speed.

"CAW! Northeast! Northeast! Dragon Hashira Ryūjin Kaidō fighting Upper Rank demon! Reinforcements needed! CAW CAW!"

Obanai Iguro, closest to the location, immediately changed course. Not far behind, Kyojuro Rengoku heard the alert and also rushed to provide support.

"Don't you dare die, kid! You still need to attend my wedding with Mitsuri! You can't die—hold on! Whatever you do, don't die!" Obanai's thoughts raced as he pushed himself faster.

After that heart-to-heart with Kaidō, Obanai had finally worked up the courage to confess to Mitsuri. To his shock, she'd accepted immediately—said she wanted to be with him, to become his bride.

Kaidō's "assist" had been instrumental, of course. Obanai's gratitude toward the younger Hashira had skyrocketed. He'd been planning to treat Kaidō to a proper thank-you meal, but the Dragon Hashira was always either killing demons or traveling to kill more demons. The dinner had been postponed indefinitely.

...

"Guh!" More blood dripped from Kaidō's mask.

Cough, cough.

Even with the Demon Slayer Mark active, he was still injured. Doma's poisoned attacks had left multiple wounds on his body, each one covered in a thin layer of ice.

"My, my! You're quite impressive! To last this long under my assault! I remember a girl who did something similar—held out until dawn. Unfortunately, I couldn't make her one with me to enjoy eternal life. But looking at you... well, you'd be delicious too!"

Kaidō slowly raised his left hand and flipped Doma off. "You're absolutely insufferable. I bet you get punched in the face constantly but still think you're popular. Also, you're a total creep!"

Doma didn't understand the gesture, but it made him inexplicably annoyed. Still, his smile remained. "Oh, but I am very popular! Akaza-dono occasionally greets me by punching me in the face!"

"I wonder if you can keep this up? Blood Demon Art: Freezing Clouds!"

Doma waved his fans, instantly filling the air with countless ice crystals that spread like mist.

Kaidō understood immediately—if he inhaled that poisoned mist, his lungs would necrotize just like Kanae Kocho's. Same fate.

"Looks like I've got no choice. Time to use 'that' technique."

...