A little background, I am from Pakistan and due to various encounters I am a firm believer of the paranormal though not really afraid of it.
This story is around 3 years old, I was 18 at that time, so I am pretty sure none of it is a figment of my imagination.
I was visiting my Cousin's house in the city of Gujrat. Their house was in a new part of the city which had very low population at that time. It was basically 3 houses in an entire street.
So during my visit, we had some talks of the paranormal and my cousins told me that they see often see their sister combing her hair in the other room even though she lives in an entirely different city for studies, they told me about their various experiences.
I tried to call out the "ghost", as I liked these type of adventures, asking it to show me some kind of signs but nothing happened until 3AM. All 3 of us were still awake talking and stuff until I saw a shadow outside the door through the gap at the bottom of the door.
I called to my cousin "Yo, Looks like your father is up and probably standing outside the door".
He looked at me and said that his father stays on the second floor. I opened the door and found no one though the room where they saw their sister multiple times was open.
I, trying to impress them, decided to sleep in that "haunted room" tonight. They kept the room closed mostly only used as a storage, I took my mattress and a pillow and laid down in that room.
During the entire night I kept hearing the sound of some kind of wrapper being crushed again and again, but finding nothing I just slept through it.
Then happened the dream. In my dream I saw my cousin, the one who lives in a different city, but the weird thing was, everything she did in my dream was completely ignorant of her normal personality.
When I woke up, I wad pretty sure I saw the ghost in my dream based on the drastic shift of habits. Though I still called out to nothing again for a sign and went back to my own home.
Now this is where I was attacked. The day I got home, things got weird. I kept hearing something scratching against wood during the night.
In the morning I woke up, parked my bike to get breakfast and my bike fell, it's a very heavy bike which fell exactly opposite the side of its weight which is impossible for even a child let alone air but I saw it fall from nothing.
The rest of the day, weird things kept happening, from my bike dying out as soon as I was in a quiet area to it starting without any faults as soon as a random person passed by it.
Random dogs following us, GPS losing functionality all of a sudden.
And it kept happening until we reached back home.
And the last straw? My bedroom door opened itself a few minutes after I asked "If you followed me from my cousin's house, give me a sign", It was not a creepy movie like opening but just enough to think that this was not air.
That's all from this experience, I have many many more personal encounters, which I might share at a different time.
Just to explain the title, My cousins had nicknamed the ghost as Demon sister.