In this story section, labeled The Heart In the Box: Kyojuro Rengoku × Reader, the following warnings will apply to all chapters:

⚠️ smut in the last chapter
⚠️ language
⚠️ VIOLENCE
⚠️ extreme blood loss.

You were a half-demon girl who loved the nightlife but wished you could go and see the sunshine. You were a demon slayer but weren't part of the demon slayer corps due to you being part of the demon that they were trying to kill. Your father was a strong demon who taught you the errors of his ways and made sure you didn't make the same mistakes he made in his life. His first family was murdered by demons, and he joined them to kill the demons responsible only to kill some innocent people and bad guys along the way.

Your mother was a demon slayer, and when they met, demons had paralyzed your mother from the waist down and were toying with her. Your father barely managed to save her and asked if he could die by her blade once someone came to help her. He stayed till sunrise in the shadows, helping her and waiting for people to show up. Eventually, someone came, but she didn't kill him.

Oddly enough, they fell in love and had you. You couldn't use your demon powers too much. Otherwise, you would get lost and may attack your friends on accident or good people, so you preferred your human abilities, but sometimes you had to use them. It wasn't your favorite, but you had to do what you had to do.

You were heading home finally after a long couple of months of traveling. You traveled to hunt demons or investigate them to see if it was a demon or an animal. If it was nothing, you would stay in town trying their food and also feed the poor if you could. You loved making food for others and loved gathering new dishes to take home to your parents. Your parents were always worried for you since they didn't know how long you would live and never see you with a guy. You were happy being alone, and you also took into consideration that you could live for hundreds of years. Seeing your children or even your husband die was something you wanted to avoid at all costs. Your father already had a plan for when your mother died, and that was to go out into the sunlight. He was already a hundred and fifteen years old, and he knew it was selfish, but your mother was the love of his life, and he had been around for ages. A good portion of that time was dedicated to hurting others.

You got onto the train with enough food to feed six people, but honestly, most of it was for you. You ate a lot, which made a lot of men stare at you in disgust because men were only supposed to eat a lot. You stopped caring what people thought of you long ago, and it made it easier for you not to fall in love with any human. You never found one that piqued your interest anyway. You were twenty years old and independent, which was what you wanted.

You took your seat on the Mugen train and smiled as you put your food boxes next to you as well as on the ground. You sighed weakly. Knowing you were going to be cutting it close, you made several areas to hide until night came again. You saw a man with several food boxes sit next to you and start eating right away.

He had flaming yellow hair with red in it. You smiled as he yelled tasty after eating, making you almost break out into a fit of laughter. People were looking at him like they looked at you.

"Hey, is that any good?" You asked.

"Yes, it is!" He said happily.

"Then here you should try this sushi and other things I made before coming here. I eat a lot myself due to my metabolism, and I learned most of these dishes from night street vendors I have visited all over Japan," you smiled.

"Night vendors? It's dangerous to be out at night," he said as you gave him a box.

"People say that, but I can take care of myself. How do you like it?" You asked as he ate some and stopped eating for a second, making you panic.

"This is amazing," he said as you smiled in relief.

"I'm glad you like it. Also, I'm sorry to tell you, but you stick out like a sour thumb," you chuckled as he looked at his clothes.

"What's wrong with my clothes?" He asked.

"Nothing, they fit your personality perfectly. I'm just saying a lot of people don't wear flashy clothes, so be careful you don't get pickpocketed," you said.

"I will thank you," he smiled, "my name is Kyojuro Rengoku it's very nice to meet you."

"Y/n L/n, it's nice to meet you too," you smiled.

You remembered his last name and knew his father was a strong demon slayer. Your mother told you before he met his now-deceased wife he asked her to marry him and she refused. You took your father's last name, and since it wasn't a famous demon slayer name, he probably didn't know who your mother was. The way he looked at you made you feel warm and made you blush a bit. You never thought about giving a human your heart, but now you were thinking about it.

"Mr. Rengoku!" Tanjiro yelled as you smiled, seeing he had friends looking for him.

"Here, I will clear some space for you three," you said as you grabbed your lunches and started to move them further down.

"Oh, you don't need to move," Tanjiro said.

"It's fine, here you three look hungry," you said as you gave each two boxes and gave Rengoku an extra one as well.

"Thank you!" Rengoku said as you smiled.

"Not a problem, enjoy the train ride!" You smiled as the train conductor started clipping the tickets.

"Did she give you the box you are eating?" Tanjiro asked, worried.

"She did; she made them herself," Rengoku said as he happily ate.

"She could be the demon we are after I don't smell a demon anywhere," he said.

"I don't think she is; if she was, she would have killed me by now," he smiled.

You couldn't get him off your mind, and you couldn't stop smiling. Maybe you could go on a date with him, but you quickly remembered you were part demon and had to forget about him. Some demon slayers might not look at you as a human being, but he seemed nice. Felt his presence, and it was calm and peaceful, just like the boy who briefly spoke. It made you wish you were human, but you knew it wasn't possible. Plus, if you were, you would have died ages ago while fighting demons.

As you thought about it and stared out the window. You started to get tired and fell asleep.