Kimetsu no Yaiba/Demon Slayer Isekai. Female lead.

Officially a slayer!

Haku woke just before the break of dawn. Nezuko was nestled in the crook of her arm, still asleep. Tanjiro's green checkered haori had been placed over them as a blanket. Haku had fallen asleep in the room with the group, unable to tear Nezuko from her. She stretched, and gathered Nezuko up, placing her into her box so the morning sun would not burn her. She headed towards the kitchen only to bump into Shinjuro. He scowled down at her. "Another one of you with a mark. Puh!" He was noticeably less hostile about the situation than she expected. Had to be his brawl with Tanjiro. While the topic of Rengoku Kyojuro's death was not argued given this time he had lived, he still started a fight with the eldest Kamado over Sun breathing. Haku smiled at him, determined not to let his foul mood ruin her good one. "Rengoku-san, good morning." Shinjuro only glared at her, taking a swig of sake from the bottle. Haku sighed. " You really should take care of your body. Your son's would want that, and so would your late wife. There will be a time when your skills as a slayer will be needed." Shinjuro was enraged. He grabbed Haku by her collar, lifting her off the ground. "A person's capabilities and limitations are set at birth. A rare few enter the world with talent, the rest are just rabble! They're dust! Of no value! You have no right to speak against my family! Not when I graciously allow you to stay here!" Haku grabbed his arm to steady herself. "Rengoku-san! You were an excellent swordsman! People remember you for saving them believe it or not! Now you are shaming your family name! Your wife's name! People who were born and blessed with greater abilities than others, have to use their power for the world, for the people. Hurting others with your power which was gifted from the heavens, and soiling your clothes is unforgivable." Shinjuro stepped back, releasing Haku who landed with a thud on her butt. He simply rushed past her back to his room. Haku had quoted Ruka, and it shook him. Haku gathered herself and went to get ready for the day. She definitely could not tell the Rengoku brother's about this.

A few weeks passed. Haku stood with Rengoku at the gates of the estate, waving goodbye to Tanjiro, Zenitsu, and Inosuke. All three were headed out on a mission and would be returning to the butterfly estate afterwards. Zenitsu had clung to her leg crying and had to be peeled off by Tanjiro. As they disappeared from sight, another figure became visible. It was Haganezuka with her sword. Haku ushered him into the estate excitedly. She sat across from him, Rengoku by her side. Hagenezuka proudly handed her the sword. "Maybe this time I will finally get to see one turn bright red." Rengoku boomed approval. "Yes! Red and ablaze like your heart!" Haku fidgeted with the blade. What color would it be? If it was black like Tanjiro's, she was dead. Taking a deep breath, she pulled the sword from its sheath and held it pointing up. Slowly the blade changed, a rainbow of color taking over the blade. It was like that rainbow stainless steel you could find utensils in. Everyone was stunned. "Has this......happened before?" Haku questioned. Rengoku crossed his arms. "Never seen it!" Haganezuka had his hands folded. "I have been blessed. One of my swords has become the first of its kind!" So this was a whole new thing. She sheathed the sword. "Well... regardless, thank you for my sword." She bowed. Haganezuka was quite pleased. At least it was not black.

Haku also received her uniform that day as well as her first assignment. The uniform was the typical female demon slayer uniform; a black skirt and black long sleeved top. She wore the half and half haori from her father and mismatched socks to match. One sock is the same red-orange as one side of the haori, the other navy blue like the other side. The back of the haori had an entwining sun and moon in the center. Her shoes were the usual sandals. Her sword strapped to her side, she headed to meet Rengoku outside. He turned to her as she neared him. "Ready for your first mission?" Haku nodded. "Yes! I think my breathing technique is refined enough that I can fight." Rengoku beamed. "Good! We will be heading to a forest not far from here. There's a small village past there and villagers must travel through the forest for supplies, and there have been reports of attacks on the villagers. Many go missing without a trace. Demon at work I am sure." Haku nodded and followed Rengoku in the direction of the forest.