My Creepypasta Oc's origins

•Ellie• (story)

Ellie was a teenager, around 15 with other older and younger siblings. There was her older sister Summer, the twin boys, Ben and Harry, the triplets, including her, her younger brother William and younger sister Hazel.
There was another three younger siblings she had, but only one of them stood out to her. That was her little brother Finnian.

He had large blue eyes and dirty blonde, short hair. He usually wore monochrome colours like grey or black, but sometimes he would wear the occasional yellow t shirt.

He was her only friend, and although everyone at school thought her life was perfectly normal, her life was a living hell.
As soon as she walked through the door with her twin siblings, her parents would let them go, leaving her behind.
They would complain to her about how she wasn't trying hard enough at home with her chores, or tell her that she was a mistake and they only wanted her other two younger siblings to have been born. It was only her and Finnian that were being told these things. They were the only children that were being complained about.

One day, Ellie woke up with a start in the middle of the night and thought up a small plan to escape from her living nightmare.

As she carefully made her way into her parents room, she reached for one of the many machetes her father had hung up on the wall of the room. As she made her way over to her parents bed, they seemed to wake with a start, making Ellie jump slightly until she realised what she wanted to do with the weapon.

Before her parents cried out, she slashed their throats, making them cough up blood and gasp for air. As their life drained away, she moved away from the scene, feeling accomplished and proud.
She made her way for each of her siblings rooms, going in order or eldest to youngest.

She reached her twin siblings room and snuck in, only to find that they were both awake and waiting for her to come for them.
As she went for Will, he fought back, scratching at her left cheek until he carved three slots into her flesh. She slit his throat, her cheek throbbing as tears streamed down his face.

"Looks like you two were enjoying life... too bad I found you..." she mumbled to the corpses in the room as she walked out.

As she was about to walk out of the house after killing her siblings, she heard whimpers from Finnian's room. She opened the door to see his hand cupped around his mouth, his eyes wide open as he sobbed. She gave him a small smile as she nodded and walked out of the house, grabbing a long brown coat and fleeing the place she used to call home. She left him there to interpretate what that kind gesture meant.