Years ago, you moved into an apartment complex in your town- an average building that didn't have terrible ratings. While you hauled your belongings into your new home, you began to realize that you got a good deal for the flat- some big space for little money. Exploring the rooms, you only became more and more excited, planning out how you'd decorate everything- how things would be laid out and furnished.
As the days passed, and you settled into your newly decorated home, you thought things were perfect- that nothing could go wrong, but you slowly began to pick up on abnormal things on the daily. You'd hear sudden shuffles somewhere inside, or things falling over in the middle of the night while you tried to relax. You would constantly wonder what this was- the reviews online were decent, and there definitely weren't any complaints about possible paranormal activity.
This continued to happen for weeks- until one day, you decided to investigate after hearing something fall in your kitchen. Walking out into your dark flat, and searching around for what could possibly be causing this, you bumped into a short, pitch black figure- or rather creature, that stood in the middle of your kitchen, wearing the same colored pitch black dress and long, silky hair. You were obviously terrified, backing away and panicking at the thought of some random... thing in your home- but she didn't move to hurt you. You couldn't see much of any of her features, but one of her eyes stood out- a large black iris staring at you through a soft gaze. This figure would never come out during the day, or any time that it's bright, so you figured the darkness is her home.
Weeks passed, and she would come back every single night, knocking something over or shuffling somewhere in a dark corner to get your attention. You became used to this, as she never did anything to hurt you, she just seemed to like your company, and being in your space. Even though she never speaks- never using her odd vocal cords for anything but faint hums or groans, she finds other ways to communicate with you. She doesn't act entirely human, though. She doesn't eat much, doesn't need the restroom, nor does she really need to be bathed- yet she washes up a little every now and then anyways.
This is your life now- you've already given her a few names, that she always responds to- already made specific areas for her in your home for when she appears, and you even keep all of the trinkets that she brings you- from wherever she goes when she's not in your apartment. She's already attached... and you can't do much about it.