Kimetsu no Yaiba Sibling Scenarios

Muzan Encounter (Older brother!GiyuuXLittle Sister!Reader)

(Y/N) = Your name
(h/c) = Hair color
(e/c) = Eye color

(3rd P.O.V)
Giyuu!!? Where are you?!" the (h/c) girl yelled, calling for her brother. "I'm right here (Y/N) ", said a voice from behind her. She spun around and smiled. "

Welcome back from your mission!", she smiled, giving Giyuu six Onigiri wrapped in a leaf.

"Why don't we split this, ok?", he said, giving her a soft smile. She took them back into her hands and nodded.

"Giyuu, I have my first mission tomorrow. I'll be gone for a few days, but don't worry. I'll be fine.", she said, nodding slightly. Giyuu was concerned, but smiled, and nodded, trusting her.

(Time skip brought to you by a lonely Giyu)

Early the next morning, (Y/N) left for the village where people were going missing, and being found either dismembered or melted. When she arrived, some people saw her uniform, and ran to her, crying and begging her to find their loved ones.

She nodded, explaining to them that she'll try her best. When night came, she got up from her bed in the inn she was staying at, slipped on her haori, and clipped her Nichirin Blade to her belt. She then left the inn and walked through the streets of the village, looking out for any demon activity, when she spotted something.

(Reader P.O.V)
Someone was dragging an unconscious person behind an alleyway. I rushed over with my Nichirin Blade out, and swung at the demon. It jumped away, leaving the unconscious person behind, so I woke him up and told him to run, which he did gladly. I turned around and readied myself to attack, but froze, my eyes widening, my body trembling in fear.

Instead of a regular demon, or even a twelve Kizuke, was the strongest demon himself. Muzan Kibutsuji. I began breathing heavily in fear, and tried to calm myself, making him smirk.

"Afraid, are we? Good. Your not a fool-", Muzan was cut off by me swinging my sword at the back of his neck, only for him to turn around and kick me away. I gasped out as I heard a cracking sound and gripped my side. I ran again, this time using an attack.

"Storm Breathing, First Form:Eye of the Hurricane!", I yelled, swinging my blade at him, but he only smirked, and hit me away again.

This went on for 30 minutes. I knew he was toying with me, and I knew I didn't stand a chance, but I still held onto hope.

(3rd person P.O.V)

However, that soon dissipated, when he stabbed her with his hand in her stomach. She screamed out, making him grin.

A marechi? Interesting.", he said, drinking some of her blood.

"I don't want to kill you yet though. I'm going to make you suffer."he said, before dragging his nail down her arm, instantly transforming her into a demon.

(Reader P.O.V)
I screamed in anguish, as he disappeared into the shadows. I looked at my reflection in a puddle and screamed, gripping at my hair. I now had blue tips in my hair, and bright, pale (e/c) eyes, as well as sharp fangs and nails.

(Meanwhile)

(3rd P.O.V)

"CAW! CAW! (Y/N) Tomioka has become a demon!!She will arrive soon!! CAW!!" her crow cried at dawn.

Giyuu looked up in shock and disbelief, as well as everyone else. They looked at the gate, and saw a figure approaching, with a thick blanket thrown over her to prevent the Sun from burning her.

The first thing that Giyuu noticed, was the sad eyes she had. When she arrived, she looked at the Pillars, and let out a sob, collapsing to the ground, bowing her head.

"I'm sorry! I'm so sorry!", she cried, covering her head with her hands in shame. Then, Giyuu walked over to her, and crouched next to her.

"What happened?", he asked her in a calm tone.

So she told him, as well as the other Pillars, about how she went to the village, and fought Muzan, and how he turned her into a demon. The Pillars were shocked that she fought Muzan and survived, but they had to tell Oyakata.

So they did and he said, that as long as she doesn't attack anyone, she can live, but if she does, Giyuu must kill her. And if he doesn't, he must commit Sepeku. He agreed, but the next morning, he found her, dead, her body holding her blade, with her head cut off. She killed herself, and she was already disappearing.