Dear Brother,

Nezuko's hand froze above the paper, unsure exactly what to say. It had been what, fifteen years since she last did one of these? It could have been longer even, time kind of blended together after so long.

The year is 2019, now more than one hundred years since those early days of working for the corps, just over sixty years since the last time I saw you. The buildings are taller now, and it's possible to get from one end of the world to the other in a day or less. If you were still here, I think you would've hated it, if your reaction to Tokyo on our second mission is anything to go off of.

The letters were a sort of coping mechanism for Nezuko, a way for her to vent whenever things started to get to her. She leaned back in her chair, looking around the small apartment, noting just how empty it was.

She didn't have very many belongings. She moved around frequently, and when she did so, she only took the most important items: the clothes on her back, a bag with other minor items, her brother's nichirin sword, and his black and green checkered haori. Setting down her pen for a moment, Nezuko walked over to her kitchen (that saw no use), and got a glass of water. She didn't exactly need to drink, but the cool liquid running down her throat was refreshing.

Being a demon in this modern world isn't easy. I have to hide my claws whenever I'm out in public, and I can't really talk that much, or else someone might see the fangs. The urban legends revolving around demons have practically disappeared, and I think I might be the only one left. The last demon I found was around seven years ago, and he'd been hiding in a cottage deep in a chinese forest, luring humans in. I didn't get much out of him before he tried to attack me. I'm sorry for using your blade without your permission, brother.

The demon slaying corps had disbanded about seventy years prior with the start of World War II. At that point, they'd run their purpose dry, having killed Muzan and hunted down almost all other demons across Japan, so it made sense to disband the organization. Nezuko, however, carried on the corps's legacy as a spiritual successor. She travelled around, searching for any hiding demons, even venturing out of Japan to find them. Every demon she found, she took blood samples from, no matter how powerful they were. She was continuing Tamayo's legacy, the same legacy Tanjirou had worked towards up until the day he died.

She continued to search for a cure to demonism.

They're calling this the 'information age', which is pretty fitting. The world has developed a massive network to share information, all available at your fingertips. A person in Europe can talk with a person from Japan with a single button press, and you can get the answer to pretty much any question you could conceive by just looking it up. Ironically, that hasn't helped at all with finding a cure, of course. I think I'm the only person alive that believes in demons anymore, so there's obviously no information about us other than urban legends.

Tamayo had died in the battle with Muzan, and the cure she'd developed was incomplete. When Nezuko had woken up, she still had the likeness and abilities of a demon, and she could still walk in the sun. The only difference was that she felt like a cloud was lifted from her mind, and she regained her full cognitive capabilities. She still had claws and fangs, and she could still use blood demon arts. She still could walk in the sun and her injuries still almost instantly healed, and the scent of human blood made her mouth water, though the urges to actually satisfy the hunger had long since faded.

Sometimes, I feel like it's pointless. I haven't been able to recreate anything more effective than the prototype cure that Tamayo outlined in her notes. I've long since used up the blood samples taken from upper moons years ago, and I only have about a drop of Muzan's blood left. I'm hesitant to analyze it until I'm completely ready, so I'm trying to learn modern science and biology so that I can analyze the blood samples myself and learn properly how to develop a cure, but it's hard. I've gone through so many different identities over the years, picking up a new one every time that I feel like someone is catching on, and every time I do, I practically have to start over. I'm just so tired of running.

Nezuko took her paper and a book to write against and left her apartment. She needed some fresh air, and the closest place to get it was the roof. Just as a precaution, she grabbed her brother's nichirin sword, hiding it inside the checkered haori. Her apartment was in the middle of Tokyo in one of the highrises, so the walk up the stairs was long, but luckily she didn't have to worry about her legs tiring.

It was windy up on top of the roof, and a breeze ran through her hair the second she opened up the door. Nezuko took a deep breath, letting the crisp, cool air fill her lungs. She didn't have a potent sense of smell like her brother, but she could still smell the ozone in the air, a scent that she hadn't smelled much until the last two decades or so with the rise of cars and mass transportation. She walked up to the edge of the roof, sitting on the ledge and dangling her feet above the street below.

She didn't care if she fell, it would hurt but it wouldn't kill her. It was currently only possible to kill her with a nichirin sword, of which she was pretty sure she had the last surviving blade.

Having a way to kill other demons that may still exist wasn't the only reason she kept her brother's sword around.

Pulling back out her letter, she continued to write.

Sometimes I feel like giving up. It's lonely, and everyone I once knew is gone. I mentioned this in a previous letter, but Zenitsu was the last one to pass on in 1991. After losing you all...I can't bring myself to make new connections. There's even people at the medical school that I've been attending on and off who are nice to me and I'm sure would make good friends, but I have to push them away, else they figure out what I really am. Even if they don't, I don't think I could handle outliving one more friend.

She could feel herself starting to get worked up, just like every time she wrote letters to Tanjirou. She wrote more of them in the early years, mostly right after he had died of old age, but she found herself returning to the habit after every time another of her friends passed on. Tanjirou first, then Inosuke, then Kanao, and then finally Zenitsu. All of them hit her hard, and the letters were her way of venting her loneliness, since she had nobody else to talk to about it, and she probably never would. Before she could get too mixed up in her emotions, Nezuko continued to write.

Every time I think about giving up, I think about you. All the way until your last breath, you were searching for a cure. Even when you couldn't walk on your own anymore, limited by your own body, you tried to help, all because you wanted to see me be able to grow old, and that keeps me going. Even though it's tough, tougher than anything I did while you were alive, I keep going because this was your dream, and your dream has become my dream.

A single tear rolled down Nezuko's cheek. Reaching up, she wiped it off with a clawed hand, flicking it off and down to the street below. She grabbed at her sweatshirt, taking a handful of clothing in an attempt to stop herself from breaking into tears. Clutching onto the pen, she brought it to the paper to finish the letter.

I'll never stop searching, not until I find a cure. Even if it takes a hundred more years, I'll keep going so that I can one day grow old and then I'll be with you again. I'll be with you, Kanao, Inosuke, Zenitsu, Mom, Dad, Hanako, Rokuta, Takeo, Shigeru, everyone. I hope to see you all soon.

Love,

Nezuko

Nezuko set down the pen, and just sat there for a moment, revelling in all the emotions. She didn't let herself get emotional very often, since doing so usually reminded her of the past that she didn't want to fixate on. Besides, she'd cried more than her fair share in her lifetime. Now, however, she just let them run their course. Anger, sadness, loneliness, hopelessness, doubt, everything that she normally didn't let herself feel. She took a deep breath, and cried a little, letting the emotions free. When she ran out of tears to shed, she took another deep breath to reel herself back in.

Nezuko took her note and held it up in front of her. With one hand, she scraped at her wrist with a sharp, clawed finger. The scratch drew blood, and she dripped blood onto the note before the wound healed. Activating her blood demon art, she watched as the piece of paper ignited with pink flames, slowly burning away. As she watched the note disappear into ashes, she let herself reminisce on all the good memories she still had, buried deep in her mind. For the first time in a while, she felt content, letting herself smile, just a little.

I hope this reaches you.

A/N: Inspired by this art - make sure to go support the artist! (replace comma in link with a period): twitter,com/Velinxi/status/1172299324119584768