Violent dream

I have had quite a violent dream a couple of days ago. Here it goes:

I was in my father's parents' home in the kitchen. There my mother's mom sat, and one of her friends, and my cat sat on a sofa. So I start hearing demonic whispers about killing my cat. I immediately pick my cat up to protect him. Then a demon possess my grandmother, heads for a knife. Now I run away to bring my cat to safety in a room nearby. The demon follows me, stabs me in the back twice. I lose balance for a while, but I turn around and stab it through through the lung then the heart with a knife I found on a table. After killing the demon, I turn back to my cat and see he has been stabbed twice.

Now I return to the kitchen, to make sure there is no more demons there. I look at my grandmother's friend for a while, and after a second, she looks at me and her eyes turned red. I stab the head a few times to make sure that it is dead.

Now I find my grandmother's body, where she sat before the possession. The body was clearly lifeless. Note that this is her body before she was possessed, not the one I destroyed in the room where I was stabbed in the back. I thought it would be interesting to see the brain, so I chopped off the top of the body's head with the knife.

A while after that, the dream ended.

forgive me if I'm wrong but could it be that your grandmother has a dark side and was emotionally abusive?

You're in your paternal grandparents' house meaning it is they you look up to and respect. The kitchen is the need for emotional nourishment. The demon must be some kind of ill will. The cat I'm not sure of, perhaps your affection for women in general, but it's a he, perhaps you have a male cat in real life.
The maternal grandmother is possessed and wants to kill the cat, your affection. The knife is hate. You try to move the cat to safety in another room, another part of yourself. The demon stabs you in the back twice, possibly meaning in the past. You find your own knife and stab the demon, but the poor cat is also stabbed twice.
Your grandmother lies dead in the kitchen, you no longer love her? Her friend then glares at you with glowing red eyes, she judges you harshly, probably from just hearing your grandmother's side of the story all the time. You stab her in the head meaning you over come this.
You think it would be interesting to see your grandmother's brain, meaning you wonder what made her the way she is.

Again I'm sorry if I'm wrong, this is a terrible interpretation and I hope it's wrong.

It is okay. I can understand if this dream is a bit confusing.

By the way, the cat is a male and I have had him for seven years in reality.