You were in the woods, and immediately, you knew you were dreaming because you saw your father gathering wood in broad daylight, which he never did.

"Nice try, but I know where I came from," you said as your father looked at you rather confused.

"I wasn't hiding from you. Are you feeling alright? You have been in the sun all day," he said as you smiled.

"I am thank you, Dad. I know you aren't real, but I'm glad you can be in the sunlight like you always wanted," you said as you took out your sword and slit your own throat, waking you up.

"Nice try, but I had a demon do this before to me. It was my dad," you said as you got up.

Everyone was asleep, which wasn't normal, and when you went to see if your demon slayer friends were okay. There were kids connected to children, making you confused. You tried to break the rope, but to your surprise, you couldn't. You saw Rengoku choking a child while he seemed to be sleeping, making you angry. You weren't angry at him, but the boy he had.

"You know working with demons gets you killed, right?" You asked as the boy looked at you terrified.

"How are you-" You cut him off.

"Awake? Well, my dad is a demon, and since I'm also half-human, he made sure I was prepared. The drugs he gave me put me in a dream-like trance, but now I can tell when I'm dreaming and what's real. Now you are going to tell me how to get them out of the trance, or I will kill you myself," you said as you revealed your demon eyes.

"I don't know how okay! I was told what to do, I just want to be with my family. My family is gone, and he promised me I could be with them," the boy said.

"Bad demons that wish people harm lie. I care very little about you at the moment to lie to you," you said as you touched Rengoku's hand, and yet he was still choking the child.

You pride his fingers loose and then tie up the boy tightly so he won't get away. You looked him over, trying to figure out how to break him free from this trance.

"Okay, I have no idea how to wake you up," you said as you tried shaking him a bit.

An idea that had a very low chance of working crossed your mind, and you sighed and then touched his face.

"Hey Rengoku, you are dreaming, and the best way to break free is to kill yourself. Trust me, it's weird, but you can do it. Also, I'm going to try something real quick to see if it works because I have no idea how to wake you up. Sorry in advance," you said as you kissed him.

"Eww!" The boy said as you pulled away and sighed weakly.

"Shut up! Look, I have no idea what you did to him!" You said as you were hit in the back with something hard and pushed almost to the back of the train.

"You broke my spell!" You heard a voice say as you stabbed your sword into the ground.

"Not that hard. You may be strong, but I'm strong enough to hold you off till morning," you said.

"Yeah, but what about the people on the train having sweet dreams?" He asked as the demon's stomach started to somehow engulf the train car.

"You bastard, well I guess we have to dance now, little man!" You said as you started to battle the tentacles that seemed to be going after you.

Most of your attacks you couldn't use, but you could use some of your demon powers if need be.

"Ice flame demon blood art first form! Artic blood flame dance!" You yelled as you ran up and down ten cars, destroying all the tentacles in your path.

"You think that little attack is strong enough to bet me?" He asked as he cut you.

"A half-blood? That's unheard of. No wonder you are so weak. Combining your human abilities with your demon abilities isn't a great idea, especially if you push your demon too far," he chuckled as you continued to fight him.

After a while, you felt someone coming your way, and to your surprise, it was Rengoku. You smiled as you quickly took his back and started fighting again.

"The others are awake and going to defeat the demon responsible for this. I didn't know you were a demon slayer," he said.

"It's complicated," you said as you took your blood from your cuts and set your blood on fire.

You quickly unleashed a fire slash that traveled quite far and burned everything in their path.

"It would be hard to explain, a demon fighting a demon," he said as you deleted an attack.

"How long have you known I was a demon?" You asked.

"Since I met you, also you said you learned how to cook all these dishes at night. Normal people would lean during the day, especially women if they aren't traveling with a companion," he explained.

"Hey, some women like to travel alone," you pointed out.

"Crime against women increases at night, especially if they are alone," he said as you couldn't argue there.

"You better not kill me after this then," you smiled as you both were protecting all the cars by yourselves.

"Don't worry, I won't. I only kill bad demons, and you are one of the few good ones," he said as the train abruptly started going off the tracks.

You grabbed Rengoku, stabbed your sword into the floor, and held on as the train flipped. The train slowed down, and you used your demon abilities to blast a hole in the side of the train.

"I guess they got the demon," you said as you started helping the humans, but you could smell blood in the air.

"They did, I knew they could," he said proudly, but you started walking away from the train.

"There hurt!" You said as you ran over to them.

"Y/n?" Tanjiro asked as you saw Inosuke was extremely hurt while Zenitsu was passed out on the ground.

"Don't worry about me. You all need to be treated, especially you," you said as you pointed to Inosuke.

"It's just a scratch. Leave me alone!" He said as Tanjiro fell to his knees.

"Looks like you won a voice said as you quickly got out your sword.

"What do you know another demon," you said as Rengoku went to your side.

"Y/n, please take care of everyone. I have no doubt in your abilities as a demon slayer, but the humans need you," he said as you looked at him oddly.

"He's strong. I can see it. Please let me help you," you said.

"The sun will come soon and kill you if we both were to fight him. I will talk to him first and see what he wants," he said with a bright smile.

"Fine, but I won't be going far," you said as you already made up your mind to die by the sunlight if it meant saving everyone here.

After a couple of minutes of helping the humans, you could hear fighting, which wasn't a good sign so you went back to the demon slayers to see Rengoku fighting the upper-rank demon with such speed it was hard to get in.

"The demon wants Rengoku to join him, or he will kill him," Tanjiro said as you looked at him, then looked at the pair fighting.

"He won't join them. I know Rengoku well," you said as he looked at you oddly.

"But you just met him today," he said.

"He smiled a lot, and he knew I was a demon and still ate the food I made. He gave me his trust the moment he met me," you said as Tanjiro looked at you shocked.

"You're a demon?!" He asked.

"Half but still, stay here," you said as you were trying to find an opening.

You managed to get in rather easily, and both you and Rengoku got knocked back.

"Go back to the others. I have him," you said. You saw he was covered in his blood and hurt badly.

"You will die if you don't stay out of the sunlight. The sun will rise soon," he informed you.

"I know, in my sheath, you will find my village I'm from. Take my sword back there, please, if I die," you said you got in front of Rengoku.

"Stupid half-breed! You think you can defeat a demon of my strength with only half of your potential! You don't know how to use your full demon powers yet or know how they feel! You're afraid of tuning out like me," he laughed as you started fighting him.

"I am not afraid, especially because I know there are people here that can kill me if I can't control myself," you said as you started to feel weaker making you realize the sun was coming up.

The demon kicked you so hard it sent you flying far. Rengoku tried to kill him but ended up fighting him longer. Then, the worst happened the demon impaled Rengoku with his arm, making you freeze in place.

"No!!" You screamed, never actually seeing anyone die at the hands of a demon before.

Somehow, Rengoku was still holding on and not letting go of him, and Tanjiro got up, and you turned your eyes into demon eyes. You were going to fully use your demon powers if you had to. The sun started coming up, but you didn't care, and your anger was getting the better of you.

You both started to go after the demon as soon as he broke free and took off for the woods. You went to Rengoku instead of going after the demon to see if you could heal him. You healed a baby bird once that broke a lot of bones when it fell out of a tree as a child, so maybe now that ability will come back to you.

"Come on, heal! I didn't it once before come on heal!" You said as you put your hands on his shoulders.

"It's okay, things like this happen all the time. At least no one died on that train," he said as you started to tear up.

"No, you were on the train and... and I can't fix this! Why can't I fix this? I did it once for a stupid bird, and it nearly killed me doing it, but why can't I do it when a human life is at stake!" You said as tears started to slip from your eyes.

"It's okay, don't cry, I lived a long life, and I did so many good things with it," he said as you looked behind you, and the sun was coming up fast.

You had to get away from and back up to the train's shadow. Now, there was no way you could heal him, making you cry out of anger and frustration.

"Y/n is that really how we deal with our problems? Sure, it helps for a moment, but just because we can't do it now doesn't mean we can't keep trying. Take a deep breath and relax," you heard your dad say as you sat on the ground and tried to relax.

"Relax, relax, relax," you said as you saw Zenitsu.

"Hey, demon slayer, I need you to do something for me," you said as he looked at you upset.

"My friend is dying, and you want me to help you?!" He asked.

"All I ask is five things. One is to permit me to heal your friend. Two is to kill me if I turn. Three to give my sword to my family if I die doing this. Four to keep me out of the sunlight while I do this and five to keep me close to him. The further away I am, the weaker my ability to heal him might be. Do you want me to try to heal your friend or not?" You asked.

Zenitsu looked over and looked at you.

"You're a demon," he said.

"If I wanted you dead, I would have killed you already," you pointed out.

"Yes, help him!" Zenitsu panicked as he went over to Rengoku.

"Demon Blood eighth form... Total concentration body connection healing!" You said as you went into a Buddha pose.

Your legs were crossed, your eyes were closed, and your hands were on your knees. All your fingers were touching your thumb, and a wave of energy was immediately released as Rengoku was about to die.

"Please don't!" Tanjiro cried as a red line hit Rengoku in the back hard.

His eye which was unusable opened up, and his injuries seemed to vanish like nothing happened at all, even though he was covered in his blood.

Tanjiro looked at him shocked as well as the other demon slayers to see he was perfectly fine.

"She did it!" Zenitsu said.

"Who did what?" Inosuke asked.

"Y/n asked me to give her permission to heal him. I told her yes," he said as they all looked back at you and then saw the red line going to him from you.

"She said to keep her close to you, so I think she's still trying to heal you. You may look and feel fine, but that might be just for looks," Zenitsu said as Rengoku got up and looked back at you.

"I guess we need to build her a box like your sister," he said as he tried to smile, but he remembered you saying you almost died healing a baby bird.

Maybe you were going to die after this.