Hello! Please enjoy this Giyu/OC imagine! Please also keep in mind that I have not read the manga for Demon Slayer, so I'm still a little iffy on what happened after the battle. I know who survived and who died, but that's pretty much it... Now, on to the story!

Aiko Tomioka's POV
As I quickly walk down the path to the Butterfly Mansion, I could feel the change in the manner of the Slayers milling around me. There was a tension that wasn't there before. Most of them never gave me more than a passing glance, despite the fact that I wasn't a Slayer or Kakushi. This was probably due to the large influx of people in and out of the Estate- and no wonder. A battle had clearly happened here. What had happened? Was... was Muzan finally dead?
I could only pray that Giyu was still alive...
I quickly enter the Estate grounds, a few belongings strung up in a sack on my back. It had taken me a day to get here, and I was tired. However, first things first... I stopped a girl with long black hair and pink eyes.
"Excuse me... I wonder where I might find Giyu Tomioka?"
The girl looked at me in surprise.
"Aoi might be upset if we disturb him. Is it an emergency? If you have a message, I can pass it on for you."
I shake my head.
"I'm afraid I need to see him as soon as possible."
She frowned.
"Why?"
I shift my shoulders, knowing that the information I was about to give would come as a shock to her. It had been kept as a secret after all...
"Giyu is my husband..."
The girl stared at me for a moment in shock, and then she smiled.
"I didn't know he was married! That's wonderful. It's probably alright if you disturb him, then. Come on! I'll show you to his room."
I bow lowly once we arrived.
"You have my thanks. Please, don't let me keep you any longer."
The girl bowed and left me to continue down the hallway.
I mentally prepared for the worst as I entered the room. It looked like a standard private hospital room. There was only one bed. I suppose having a private room was one of the benefits of being a Hashira.
I could immediately see that Giyu was lying on the bed. He appeared to be asleep. I approached him as quietly as I could, and was relieved to observe that he really was asleep, and not...
I shook those thoughts out of my head as I examined my husband more closely. I could immediately see that his right arm was gone from the elbow down. He also had multiple bandages all over his body. He looked terrible, but better than I had dared to hope for.
I quietly pulled up a chair and sat beside him, reaching for his remaining hand. I held it gently as I patiently waited for him to wake up.
Ten minutes later, the door opened. A young woman with black hair and two blue butterfly hair clips came in. She had fresh bandages in her arms. She started when she saw me, obviously not expecting a stranger. I smiled at her.
"Hello there. My name is Aiko Tomioka. I came to make sure my husband was alright. I hope I will not be in the way if I sit here?"
The girl nodded at me.
"That's alright, Lady Tomioka. I'm just here to change his bandages." She paused. "I'm Aoi by the way."
"It's a pleasure to meet you, Aoi." I smile at her. "May I ask... what happened here? Why are so many people injured?"
Aoi looked at me in surprise.
"You don't know?"
I shook my head.
"I came here because my husband was three days late coming home, and I hadn't heard anything from a crow or Kakushi. When I got here, it looked like a battle broke out..."
Aoi nodded, as she began to change Giyu's bandages.
"Muzan and the Upper Moons attacked the Master's Mansion three days ago. Although many lives were lost, Muzan was finally defeated."
I gasp, lifting a hand to my mouth.
"He... he's finally dead? For real?!"
Aoi smiled.
"Yes, he is, Lady Tomioka. The Corps is also officially going to be dissolved, although that hasn't happened yet because of all the cleanup."
I smiled. My husband and I could finally have a peaceful life.
I looked down at his prone form.
"And what of his injuries? Will my husband be okay?"
Aoi sighed.
"His injures aren't fatal, although it may take some time for him to wake up. He has a lot of broken bones, some internal bleeding, and, of course, his arm. That injury is the most concerning. However, we managed to treat him before he could lose too much blood, so he should be alright."
I sigh, rubbing the bridge of my nose.
"That's a relief. Thank you for taking care of him, Aoi."
Aoi smiled.
"Don't thank me, it's my job."
She finished changing his bandages before leaving. I grabbed Giyu's hand again, letting out a deep breath.
"I hope you wake up soon, my love... there's something I need to tell you..."
I gently rub my abdomen as I think about the child growing inside of me. Giyu's child.
I sit there for an unknown amount of time, just holding Giyu's hand and talking to him. After some time, someone knocked on the door.
I looked up.
"Who is it?"
The door opened, and I was surprised to see the girl from earlier with black hair and pink eyes. She was holding my husband's haori. I gasped when I saw it. I was so focused on my husband's wellbeing that I had neglected to locate one of the most important objects he owned.
The girl smiled at me.
"I was trying to fix it before you came. I was hoping that would help him wake up... my name is Nezuko by the way. I apologize for not introducing myself earlier." She bowed politely as I did the same.
So this was Nezuko? Giyu had told me about her. Did she manage to become human again? She didn't look like a demon, and she didn't have fangs when she smiled. I smiled at her.
"It's alright, dear. I'm sure it's been a stressful time for all of you. And thank you for looking after my husband's haori... did he ever tell you the story behind it?"
I motion for her to sit with me, which she did.
Nezuko shook her head as he carefully passed me the haori. It was nearly torn to shreds, and would clearly take time and effort to repair.
"No, Tomioka-San never really talked much."
I chuckle.
"That makes sense. However, considering how much you and your brother mean to Giyu, he'll be alright with me telling you the story."
I ran my hands over the red shreds of fabric.
"A long time ago, when Giyu was a child, he lived with his older sister because his parents passed due to illness. Unfortunately, she was killed by a demon while trying to protect him. Giyu ran away when no one believed his story about how she died, and was saved by a hunter who brought him to Urokodaki. The red part is half of her kimono.
"While he was being trained by Urokodaki, he met a friend, Sabito. Together, they entered the final selection. However, Sabito was killed by a demon on the final day. The green and yellow side is the yukata that Sabito used to wear. This is how he keeps them with him and remembers them. After Sabito died, he never really opened up to anyone, believing that they would die due to their association with him. It took him ages to open up to me, and I'm his wife."
Nezuko gasped.
"So he lost his sister and friend too... that's horrible. No wonder he's so distant. I'm just glad that the three of are here to make sure he's not alone."
I smile at her.
"That's right. We'll make sure he's never alone again."
Nezuko left soon after that, stating that she was going to see if Aoi needed any help.
Aoi returned about an hour later to change Giyu's bandages again. She also brought food, which I was grateful for. I didn't even realize I was hungry until the food was in front of me. I thanked her profusely for her thoughtfulness.

Slowly, the weeks began to pass by. I decided to stay in the mansion while I waited for Giyu to wake up.
I started working at the mansion, and became friends with many of the people staying there. One of these, surprisingly, was Sanemi Shinazugawa, the Wind Hashira. He was shocked to learn who I was, but he had seemingly changed his mind about Giyu during the battle, so he didn't mind my presence. It wasn't long before we became like siblings.
It was at that point that I explained to him some of the reasoning behind some of Giyu's seemingly questionable actions, like the time he missed three Hashira meetings in a row. Back then, Sanemi had accused him of slacking off.
"We have been trying to have a baby for a long time now," I informed him as we walked through the garden. "There were three failed attempts before this one. During all those times, Giyu didn't come to the meetings because he was both helping me as I grieved and grieving himself. This baby I'm carrying now is a miracle." I gently rubbed my belly.
Sanemi looked away.
"I am sorry for how I treated your husband, and you by extension. I should have asked questions before making assumptions. That was wrong of me."
I shake my head.
"I've already forgiven you. You know that. Just let this be a lesson for you in the future, alright?"
The rest of our walk was completed in silence.
After that, I went to find Nezuko, so we could keep fixing Giyu's haori together. Between Nezuko and myself, Giyu's haori was nearly repaired. I kept it with me at all times, sometimes using it as a blanket. The familiar feeling of the fabric was comforting.
My pregnancy progressed as well. Aoi or Kanao gave me weekly checkups, and confirmed that the baby was doing well, much to my relief. I was afraid that I would lose this baby as well...
Before I knew it, three months had passed since the final battle.
By all accounts, it was a normal day. I dressed in a kimono that hid my belly. It was not that I was ashamed, I just wanted Giyu to be the first person I told- outside of Kanao, Nezuko, Sanemi, and Aoi of course.
I went inside Giyu's room and closed the door behind me gently, just like normal. I sat at his side, talking to him, telling him about what was going on around the mansion and asking for him to wake up.
I stopped talking as I suddenly let out a yawn. My pregnancy often made tired. Before I knew it, I was nodding off, his hand still clutched in mine.
I was suddenly jerked awake when my hand was gently squeezed. I yawned, rubbing my eyes as they peeked open. I gasped when they met deep blue ones.
"Giyu! Darling!" I gasped, my free hand covering my mouth in shock.
He gave me a weak smile, and opened his mouth, clearly trying to speak. However, all that came out was a weak croak.
Reluctantly slipping my hand out of his, I helped him take a drink of water. While he drank, I turned to his crow, who, like myself, rarely left his side.
"Go alert Aoi and Kanao that he's woken up!"
The bird quickly flew off, and I turned back to my husband.
"You've been out for three months, darling. Take your time."
He gave a weak nod, and cleared his throat. When he tried to speak again, his voice was much clearer.
"D-d-dewdrop... y-y-you're h-here..."
I smile, grabbing his hand again.
"Where else would I be, darling?"
Giyu smiled at me again.
"D-demons are gone... w-we can f-finally have p-peace..."
I smile.
"That's right, darling... and I think it's time I finally tell you about that surprise, yeah?"
I gently guide his hand to my abdomen, so he could feel the baby bump. I grinned at his shocked expression when he realized what I was trying to tell him.
"I-is this... r-real?"
I smiled.
"Yes, darling. I'm four months pregnant. I was going to tell you sooner, but then the battle happened, and you've been out ever since."
I press his hand against my cheek.
"I'm so glad that you're okay, darling..."
At that moment, Aoi and Kanao entered the room. They bustled around Giyu for a few minutes, taking his vitals and asking him questions. His injuries were mostly healed by now, so most of the bandages were gone.
Once they were satisfied, they told us that Giyu could try to begin his rehab training by tomorrow, although it wouldn't be as brutal as normal because he no longer needed the strength of a Hashira. That made me smile. He no longer needed to be strong.
The next day, I got to his room bright and early. As expected, he was already awake, but was struggling to dress himself with only one hand.
I quickly approach him.
"Let me help you, my love!"
With my help, Giyu was ready for the day. However, I could tell something was wrong. I looked at him.
"What's wrong, darling? Does something hurt?"
Giyu shook his head.
"I'm alright. It's just... you have a husband who can't even dress himself now. How can I look after you and our child?" He slid his hands across my bump.
I sighed, cupping his cheeks.
"You protected us by defeating Muzan. It's time for us to take care of you, alright? Plus, I don't think we'll be abandoned by the ones who care about us. We'll get through this. I promise." I reach up and gently kiss him.
Giyu sighed, but gently kissed me back, showing his acquiescence.
I left him at his rehab training, as I had plans of my own. It didn't take me long to find Nezuko, who was visiting Tanjiro, who was still unconscious.
I smiled at her as she quickly went towards me.
"I heard about Giyu! Aoi told me this morning! I'm so happy for you!"
I chuckle and squeeze her hands.
"Have you been to see him yet?"
She shook her head.
"Unfortunately, I haven't been able to. Aoi told me to let him rest. Can I see him today?"
I smiled and nodded.
"Of course, darling. You can come with me to pick him up from his rehab training after lunch. Is that okay with you?"
Nezuko accepted, and we spent the morning doing various tasks around the mansion, although I had to rest soon for the baby. Being pregnant was no joke, and I had to be very careful so I wouldn't lose the baby.
Sanemi came by at lunchtime, and Nezuko and I welcomed him in.
"Do your injuries hurt?" I asked him.
It wasn't like him to visit out the blue. He shook his head.
"I heard Giyu was awake. I wanted to talk to him. Is that okay with you?"
I think for a moment.
"I'm fine with it, but he may not be ready. I'll talk to him first. Would you like to stay for lunch?"
Sanemi declined, but said he would be back tomorrow.
That evening, after a day of people welcoming Giyu back after his coma, we finally had a moment to ourselves.
We were curled up in bed, my head resting on his chest, listening to his steady heartbeat. His arm was wrapped tightly around me.
"Giyu...? Can I talk to you?"
I felt him nod.
"Of course, dewdrop. You can always talk to me about anything."
I nodded.
"While you were in a coma, I made friends with Sanemi Shinazugawa. He's like a brother to me. I explained some of what's been going on with us, and he realized that he's treated you wrong. He wants to apologize and make peace. Are you willing to talk to him?"
For a moment there was silence, and I panicked.
"I-sorry! I shouldn't have brought it up! I-hmph!" I was cut off when he kissed me. I felt him chuckle.
"I'm not mad, dewdrop. I'm just surprised. You're both so stubborn, so I thought you'd be at each other's throats all the time if you did meet. I'm happy that you get along. I'm fine with talking to him, of course. He's always been a valued comrade to me."
I smile.
"That's good, because he's coming by tomorrow."
Giyu pretended to be upset that he didn't have enough warning, but the "argument" soon dissolved into laughter.
"I'm so glad that you're awake, darling," I snuggled into his chest.
I fell asleep as he kissed the top of my head.

And that's it for part one! I've literally had this story in my head for ages once I realized that there's like no stories out there with a Giyu/OC that happens after the final battle. I wanted to make one for myself. I hope y'all enjoy the first part of this! I'll hopefully complete part two in the next week or so.
❤️DaughterofHalt❤️