Kimetsu no Yaiba/Demon Slayer Isekai. Female lead.

First Mission

The moon was high in the sky when they entered the forest. The dense trees limited visibility. There was a defined trail from the constant travel of the secluded villagers to head into the larger area a few miles out. Haku walked nervously behind Rengoku. She had yet to fight a demon head on, though fighting Rengoku was harder than she could imagine, so if it was a low rank, she figured she would be fine. After a while, the pair was thrown into alertness by a woman's scream. "Let's go!" Rangoku called out and the two rushed towards the scream. A woman lay on the ground with a man holding her hand. Blood was on the ground in between her legs. "My baby! My baby! It took my baby!" she called out grief stricken while her husband shook and cried beside her, a small gash on his arm. She was pointing deeper into the forest. Haku's eyes widened. This woman had given birth in the forest and the demon had taken her newborn baby. A pink haori lay on the ground, obviously used to wrap the child. Without much thought, Haku grabbed the haori and ran in the direction the woman pointed. Rengoku called out to her "Haku wait!" She did not hear him. Other demons had come to the smell of the woman's blood and Rengoku could not follow Haku.

Haku caught up to the demon. The demon was female, stood at the same height as Haku, wore a simple pink kimono with a yellow sash, her hair was long and black with yellow ends, and she had three horns on her head. She had the baby in her arms. "Stop, demon! Hand over that baby!" The demon landed on a tree branch, and Haku jumped on to one just across from her, hand on sword. The demon gritted its teeth. "Filthy demon slayer! One move and I will snap its neck! Makes no difference to me, I can eat it anyway!" Haku breathed in, steam around her lips. She rushed forwards. " Inyo breathing, second form, Kukan!" She instantly located the weak point at the demon's shoulders and chopped her arms clean off. She snatched the baby and jumped back to her branch of the tree. The baby cried, terrified and cold. "There, there. I'll get you to your momma, don't worry." Haku soothed as she wrapped the pink haori around the infant. She held the babe in one arm and her sword in her free hand. The demon meanwhile was slowly regenerating, spitting curses at Haku. Suddenly it lunged towards her. Haku went to dodge, but the demon's arm twisted around and extended abnormally, catching her by the waist. Nails dug into her side and she slammed against a nearby tree. The arm let go, and Haku fell to the ground with a thud. She held the baby close to her, keeping it as safe as possible. She quickly shot up to dodge another incoming attack. She sliced at the arm, managing to cut it off. She ran away from the demon, looking for a safe place to deposit the child. She could not fight this one handed. She came upon a hollowed out tree, and slipped the baby into the hole. She turned and rushed back towards the demon. It stood before her, smiling menacingly, "Ah, your blood smells amazing. White hair, red eyes, and a sweet smell. You must be the girl my Lord is looking for." Haku froze. Muzan was looking for her? Akaza must have told him about her and how she taunted him with Koyuki's name. "What does Muzan want with me?" she demanded, blade pointed at the demon. "Who knows, I don't ask questions. I love to eat babies. So soft, sweet, and tender. That's all I desire, and if I can do that, I could care less. Just follow orders." It sent its arms flying at Haku who dodged and blocked as much as she could. One arm snaked around under her, launching her into the sky. "Inyo breathing, fourth form, Cycle of the Four Seasons!" She twisted her body 360 degrees to slash all incoming attacks. She landed on the ground and did not hesitate, bouncing off her foot she thrust herself at the demon. "Inyo breathing, third form, Unification of Kon and Haku!" A downward slash beheaded the demon, leaving a trail of heart shaped sakura petals. The demon turned to dust. Haku was breathing heavily. She had used quite a bit of stamina. She sheathed her sword and went to retrieve the baby. She reached into the hollowed out tree and gathered the baby in her arms, soothing and cooing to it. At that moment, Rengoku appeared beside her. "Haku! Are you well? I see you killed the demon and found the baby. Good job!" Haku turned to Rengoku smiling. "Yes. I am fine. A few cuts and scrapes, but fine. What about you?" She scanned over the hashira and did not see a single blemish. "Perfectly fine! Come let us return to the couple." Haku nodded and followed beside Rengoku, smiling down at the baby the whole time. It was sleeping soundly, fully aware it was safe now. Rengoku was watching Haku, arms folded. "You will make an excellent mother." He said half to himself. Haku jolted. "Huh? Really? I dunno..." she blushed, as did the flame hashira. They continued on in embarrassed silence.

When they reached the couple, the woman was sitting up in a cart. The husband had gone into the village for one to transport her home. Haku handed the baby to the mother, tears streamed down the woman's face. "Thank you. Thank you so much." The husband patted her back. "Yes, thank both of you. Truly." Haku smiled and Rengoku boomed. "It is the duty of us demon slayers. No need for thanks!"

After returning to the estate, Haku bandaged her side. The wounds were not deep. She did not want Rengoku to see as the blood seeping out was the abnormal blue she would never get used to. Her first mission had been a success. Her kasugai crow had brought a note from Kagaya congratulating her on a job well done.