Kimetsu no Yaiba/Demon Slayer Isekai. Female lead.

Infiltration: Daki and Gyutaro

Haku exited the room she was given to change in. Outside stood Tanjiro, Zenitsu, and Inosuke plastered with make up and dressed as girls. Frankly, they were hideous girls. Haku messed with the hem of her sash. She wore a dark purple kimono with wisteria flowers designed on it, a red sash that matched her eyes and light makeup. Her lips were cherry red. Uzui hummed approval. "I'll be lucky to find you three houses to stay in, but at least Haku will be a cinch." Haku blushed. "Come on Uzui." The trio nodded agreement. Zenitsu fawned. "Haku you're so pretty."

When they arrived at the first house, they wanted Haku, but Uzui brushed them off saying she was for a special client so they chose Tanjiro, now dubbed Sumiko. Inosuke, now Inko, was snatched off the street leaving just Zenitsu, now Zenko, and Haku who was being called Yuki. Uzui brought them to the Kyougoku house where they paid a hefty sum for Haku and got Zenko free. Haku spent her time doing little things around the house. They hoped to hold an auction for her soon for her first night, but Haku knew they'd be gone before that. She sighed. She had not been around Zenitsu the whole time and she knew by now he had been abducted by Daki. She had made a point to avoid the Oiran for her own safety. She headed up onto the roof to meet up with Tanjiro, Inosuke, and Uzui. The three were already there. "Hi guys." Tanjiro and Uzui nodded while Inosuke boomed. "Hi Maku." Haku sighed. "It's Haku, Inosuke." She was not really too annoyed since this was simply one of his traits. Uzui was solemn. "Look. I made a grave mental error in my hurry to find my wives. You two need to leave, and Haku I'll have you leave with my wives." Everyone protested. "Look Uzui. I need to tell you something important." Uzui grabbed her by the waist and vanished with her. He landed with her in a nearby alley. "Alright. Go on." Haku took a deep breath, stepping out of his embrace. "Listen. The demon here is an upper rank. Kaguya-san agreed I should not reveal how I know all of this, but I do. In fact it's a pair of upper ranks." Uzui was wide eyed, mouth agape. Haku continued. "I thought it was a possibility so my crow informed Kagaya-san, but all the hashira are on missions right now." Uzui gritted his teeth. "So my wives are in serious danger." Haku nodded. "Yeah, but I assure you they'll be fine. You get going, I can get back to the house by nightfall." Uzui hesitated, obviously a gentleman, but relented and took off.

When Haku arrived back at the Kyougoku house, there was already the rumble of battle. She rushed inside and up to her room where the muscle mice waited with her gear. She quickly changed back into her uniform and haori. She decided it best to head to Tanjiro. Nezuko was already on a rampage. Haku rushed to Tanjiro who was unconscious on the roof. She lifted him up. "Tanjiro! Tanjiro! Nezuko needs you! Wake up!" she called out to the eldest Kamado. Tanjiro jolted awake. "Haku..... Nezuko! She's in trouble!" Haku nodded. "Yeah, we have to go." Haku helped Tanjiro to his feet. They rushed toward the fighting Nezuko. Tanjiro caught her just in time, before she bit a human. His sword was placed in her mouth. Haku turned to the woman Nezuko had lunged at. "You have to get out of here." The woman nodded and left. Nezuko flew upward with Tanjiro latched on. Haku jumped up with them after assuring the woman was gone. She stood face to face with Daki. She drew her sword. Daki glared at her. "Well you're not bad looking. wait ... You're the one Lord Muzan is after! What luck! I get to kill the demon girl, a hashira, and deliver you to Lord Muzan! Surely he will reward me!" Haku spat. "No way! I won't allow it!" Suddenly, a gust of wind blew her hair around as Uzui entered the room, beheading Daki. He crouched in front of Nezuko. "So this is Kamado Nezuko. Flashy way to demonize. Fight isn't over! Do something about your sister. Dumb brats have no place on the battlefield. Sing her a lullaby or something." Nezuko kicked the ground, throwing her and Tanjiro outside.

Daki sat on the ground, head in her lab crying. "How dare you cut my head off! I'm upper moon six!" Uzui turned with his face expressionless. "No way you're an upper moon. Just die already." Haku inched closer to Uzui. "Listen Uzui, she is an upper moon. Inside her is her brother, the real upper moon six." Daki screamed. "Onii-chan!" The room seemed to darken as Gyutaro emerged from his sister's back. Uzui lunged forwards with an attack, but Gyutaro dodged, taking him and his sister to the other end of the room where he put her head back on. He soothed her and scolded her, aiding in healing her wounds. Haku leaned into Uzui. "He uses sickles and poison. Don't get hit." Uzui smiled nervously. 'It's plain creepy how you know this, but I'm trusting ya alright." Uzui went to move, but Gyutaro was too fast. Haku managed to jump in between and stop Gyutaro's sickle from cutting Uzui. Gyutaro jumped back. "Well, such a pretty little thing. Oh, the one Lord Muzan is after huh. Nice." He looked back at Uzui. "And you. Perfect skin, you're tall, meat on your bones. I can't gain weight no matter how hard I try. Will you just die!" Uzui dropped, exploding the floor out from under them so that they fell to the bottom floor. He instructed the civilians to run. Gyutaro jumped down with Daki on his back. Uzui rushed forward, kicking Daki into the air and swinging his blades at Gyutaro. Haku jumped back out of the house. Uzui then threw bombs damaging Daki as she slashed them. She was again beheaded. Tnjiro, Inosuke, and a sleeping Zenitsu appeared with them. Haku turned to them "You three take care of Daki, Uzui and I got Gyutaro!" The trio all nodded agreement and led Daki to the roof. Haku returned her attention to Uzui and Gyutaro who were now in a heated battle. Blood blades bent around and tried to get Uzui from behind. Haku jumped in, blocking the blades, breathing in and shifting them away. Uzui was able to catch a moment. "Sound breathing, fifth form, string performance!" blades spinning he rushed Gyutaro, backing him out into the street. Haku rushed out to join, slapping wisteria laced sutra onto her blade. She needed any kind of boost possible.