A/N:: This is based of my own headcanon for Gumi and Gakupo. In other words I envision them being brother and sister but not blood related like Gumi and Gumiya. So in other words, after Gumi and Gumiya were separated at birth Gumi was sent to live with the Kamui family~ :D

Title: What Big Brothers Are For.

Gakupo was reading a book he had borrowed from his school library. This was one of the few times where he had the entire house to himself. He shifted uncomfortably on his couch, still wearing his school uniform. He would have changed out of it already but according he had to look "respectable" by the time they had gotten home. Tonight was the night he would meet his new little sister, a child his parents had adopted from their local orphanage. He didn't know what other outfit he owned could be considered respectable enough so he just kept his school uniform on. I wonder how she looks like. She's supposed to be pretty young… Gakupo found himself thinking as he awaited the new arrival.

In the midst of all his daydreaming, Gakupo almost didn't notice his parents come in through the front door with their new arrival. He looked up from his book to see the little girl with bright green hair being held by his mother. She put the girl down and introduced Gakupo as her new big brother. He stood up from the couch and bent down to greet the girl.

"Konnichiwa. So, what's your name?"

"K-konnichiwa. I'm Gumi."

"Well, I'm Gakupo, Gumi-neechan."

"You're m-my big brother?"

"That's right. And do you know what that means?"

"N-no…"

"Well as your big brother, I'm here for whatever you need. Within reason."

"Even for just hugs?"

"Of course. That's what big brothers are for." He grinned at her, patting her on the head.

For a while, Gumi seemed to be fitting in perfectly with the Kamui family. Gakupo took it upon himself to be a model older brother for Gumi. He would say that it was because his parents were out of the house most of the time thanks to their jobs. But he couldn't help but feel some pride over the job he was doing.

However, for a couple of weeks Gumi started having nightmares. It got to the point where she couldn't sleep through the night properly. One night from a particularly terrifying dream, she got up in the middle of the night, seeking some form of comfort. She went to her parent's bedroom but stopped. She remembered how often they would complain about the stress of their jobs. Disturbing them in their much needed sleep would be bad, she figured. Soon enough she found herself about to knock on Gakupo's door, stopping again. She didn't want to disturb him either after peeking inside and seeing him sleep so peacefully.

She sighed softly and turned away from the door when she heard him call her name. By the time she had turned around, he was there in his pajamas and rubbing his eyes sleepily.

"Gumi-neechan, what's the matter?"

She threw her hands up and shook her head frantically, "N-nothing, Gaku-nii. I just-"

"Couldn't sleep?" Gakupo interrupted. She looked down as if the floor was suddenly more interesting and nodded. "Hold on a second."

Gakupo disappeared into his darkened room, returning with a carrot plush doll that had arms and bright eyes. "This is Ninjin-san. He may be a carrot, but he's super tough and will fight off any mean monsters that lurk around in the dark."

Gumi looked at Gakupo in shock, "I-I can have Ninjin-san? Isn't he yours though?"

He shrugged and handed over the carrot plush, "I'm too old to need him. It's better if he was held by someone who needed him more."

Gumi grinned at Gakupo and took the plush, ready to head back to her room. Gakupo stood by his door as he watched Gumi hop off, stopping short of her bedroom door. He sighed as she turned hesitantly back towards him.

"You can sleep in my room tonight if you want."

And that's what happened whenever Gumi had a really bad nightmare. Gakupo would occasionally wake up in the middle of the night to see Gumi cuddled next to him, holding Ninjin-san close to her. He would always smile down at her before settling back to sleep. The two were hardly seen without each other. But things changed as Gakupo got older and Gumi was reconnected with her lost twin, Gumiya. Gakupo could tell she no longer needed to rely on her big brother now that she had Gumiya ad he convinced himself to be okay with that.

One stormy night, Gakupo, now an adult, heard a knock at his door. He opened it to see a soaked Gumi.

"Gumi-neechan! What are you doing here? Were you out in this storm?"

"S-sorry Gaku-nii, but I didn't know there was going to be a storm and there was no more cabs outside and-"

"Don't worry about it. Just get inside and dry off."

Gakupo lent Gumi some clothes, al beit loose fitting ones, to sleep in while he put hers up to dry. He called up Gumiya to let him know she was was safe and prepared to go to sleep. Except as he was about to get into his bed, he noticed Gumi was by his door. He knew why before she could explain.

"Couldn't sleep?"

"Sorry, Gaku-nii but… I don't feel comfortable in that guest bedroom."

"It's alright, Gumi-neechan. You can sleep in here if you need."

Without a second's notice, Gumi was in his bed. He laughed to himself. All that's missing is Ninjin-san, he thought to himself. Once Gumi got comfortable, he started to get up.

"Where are you going, Gaku-nii?" she asked, eyes still closed, "You're not sleeping here?"

"Gumi-neechan, we're not kids anymore. In fact, I'm an adult. It's not appropriate for us to sleep in the same bed."

"B-but, you're my big brother. I still need you." she hugged a pillow, "You said you would be here for whatever I needed."

Gakupo was shocked she still remembered that promise even though she was pretty young when he told it to her. But he smiled and got up to get something from a closet. Gumi openned her eyes as he handed the object to her.

"N-ninjin-san?"" she exclaimined, holding the plush in shock, "You kept him?"

"Just until you needed him again. Good night, imouto"

"…Good night, anikichan"