Tanjiro and Zenitsu were in the middle of the fight with one of the strongest demons they ever fought. They were barely able to stand on their feet at this point. Nezuko got out of her box to help her brother in the fight. Just as she was about to attack, the demon's head has been cut off and crushed. The huge body felt to the ground, revealing a man stading behind the demon. He was wearing f/c clothes and his eyes were shining red. Tanjiro and Zenitsu were ready to attack. He was a demon as well.
-It's okay, I'm not going to hurt the three of you. - he said waling up to them. - In fact, I believe we will be useful to each other.
-Who are you? - asked Tanjro. Nezuko watched the handsome stranger with curiosity.
-I'm Y/n L/n. - he introduced himslef.
-You're a demon. - said Tanjiro.
-I am. - nodded Y/n. - I believe we have a common enemy and if you'd let me, I can explain it all to you. Including how I found you.
-We shouldn't trust a demon. - said Zenitsu.
-You're traveling with one. - chuckled Y/n. - Plus you have something dear to me, so you can be sure I won't hurt you.
Tanjiro didn't feel any bad intentions in the demon's aura, so he decided to let him speak. They set up a campfire and sat down around it. Tanjiro noticed that it was in the open area. Once the sun would come up, it would burn Y/n, since he didn't have any place to hide.
-So. - said Y/n, getting their attention. - I'm looking for Muzan Kibutsuji. My intention is killing him and reclaiming the title that belongs to my family. I'm a member of the royal family and my father wants the crown back. That's why Muzan has to die.
-Why do you need our help? - asked Zenitsu.
-I don't. - Y/n shook his head. - I want it, becasue you've seen him recently. And I need to protect my mate. - he added glancing at Nezuko, who was looking away with a light blush on her face. Y/n's eyes softened.
-How my sister can be your mate? -asked Tanjiro, baffled. - It's impossible.
-I believe that's the reason Muzan attacked your family. - sighed Y/n. - I think he wanted to challange me and by turning her into a demon, he pissed me off beyond belief. But at the same time, I could find her. She didn't have any smell when she was human. I'm seeking for revenge for her and for my family.
-How do you expect it to work when Tanjiro will turn her back into human? - asked Zenitsu. He was jealous and he wanted to anger the demon, who was taking his chances with Nezuko away.
-That wouldn't be necessary. - said Y/n.
-What do you mean by not necessary?! -yelled Tanjiro. - She can be killed by sun and she needs a bamboo muzzle in her mouth! She can't have normal life!
-Tanjiro, calm down. - Y/n looked at him. - Do you see any muzzle on my face? Did I attack you for blood?No? If Nezuko will drink my blood and accept me as her mate, she will become one of the royals as well. And royals don't have to eat people, we are not afraid of sun either. She can have a normal life. If you changed her into human, what will happen? She will get old and die at some point, and I will be left alone without my love for next couple of centuries. You have no idea how long I waited for her. - Y/n didn't notice when his eyes got watery and a tear ran down his cheek.
Tanjiro watched him with eyes wide open. This extremely dangerous demon was honest with him. Nezuko's eyes were filled with worry as she moved closer to Y/n. She wiped Y/n's cheek and pulled him in her arms. Y/n hugged her back. Tanjiro wanted to protest, but he couldn't.
-I promise that I will never hurt you baby. - Y/n whispered in Nezuko's ear. - Will you let me help you?
-What will she need to regain her power? - asked Tanjiro.
- Sleep, my closure and food. -retorted Y/n, still holding Nezuko, who moved in his lap. - Roayls can easily live among humans. That's how this traitor Muzan is hard to find.
-Will she be safe with you? - Tanjiro needed to hear the answer to that question.
-I swear to my life that she will. -nodded Y/n.
-Then you can change her, if she let's you. - whispered Tanjiro, loud enough for them to hear him.
-Are you really accepting that? -Zenitsu couldn't believe his ears.
-Can't you see that Nezuko wants to be around him? - asked Tanjiro, looking at the two.
Y/n was explaining to Nezuko what he was about to do. In the end he asked if Nezuko wanted that, and she responded with a nod. Y/n took his shirt off and held Nezuko in his lap. Then he took her muzzle off.
-Bite baby. - he said pulling her face to his shoulder.
Nezuko hesitated for a moment, before Y/n urged her to do it. She decided to trust him and bit him. Y/n grunted in pain. Nezuko drank a lot of his blood before he managed to pull her away from the wound. It healed immediately. Then Y/n kissed her. Nezuko kissed him back right after. Y/n pulled away after few seconds. He would prefer to kiss her while being alone with her, not in front of a guy who's crushing on her and her brother.
-Nezuko? - said Tanjiro. - How do you feel?
-Good. - she said. Tanjiro wated to cry, it's been so long since he heard her speak. - Thank you Y/n. -she said smiling sweetly.
-It was my pleasure baby. - Y/n smiled back and pecked her cheek.
