Do you have a backstory for your Sims?

I usually write it in their sim bios and family bios. I'm tend to fridge-horror story, such as Sinister Sins band have five members, but people only can see four,


And the fridge-horror story of Chunyu family. Chunyu siblings is from a new poor (I don't know what's the antonym of new rich in English) family, one day the younger brother, a shock rocker, Yin suddenly turned into vampire, the older sister Ye took him to Bridgeport. In TS4 Yin married to a female vampire Ellen Sharma, and have two kids Yingzi (Shadow) and Hanguang (Cold-light).
But


There's an ancient-looking ghost, Shuixian (Daffodil) Chunyu. He was a wizard (or "internal power" user, according to his Wuxia background), he likes bullying certain type of people because he thinks he's uphold justice, then he being wanted and escaped to an outcast group (allusion to the Villains Valley from many of Wuxia works). But people in this group also afraid to him,


Daffodil's surname is also Chunyu, it's a very rare Chinese surname. Although have same very rare surname doesn't mean they're certainly Kindred, but who knows. ?

I also have some true crime inspiration. The three villain ghost, Ashley Ramirez, Theodora Roseland, Dederick Dahmer. Their names are hint at their real life reference, and

Daffodil is reference to the Dnepropetrovsk Maniacs and Philipp Budeikin, Gore Grieve is reference to IRA snipers (I don't know if IRA have Romani descent member, but Gore is the outsider character setting).

i havent but in the future i may write one too

I do like to think about my sims' backstories but I don't write it anywhere, it's just im my mind and affects my choises for them in current story.

One of my simmies, names Tracy, was initially created as another sim's girlfriend (played in Sunset Valley). When I started to play with her she was a young adult, rebellious, rock musician.
After a while I decided to create a brother for her (Jerry), which I also played with seperatly in other saves (in Riverview).
Then I had an idea to create a younger version of both of them, as teens, plus their parents and another younger brother, the story took place in Twinbrook. There, Tracy was actually a nerdy girl and the parents had a complicated divorce story.
So anyway I did thought about the backstory later in game, but my gameplay was not linear.


Also I once created younger versions of most of Sunset Valley townies just for fun but I did not end up playing with them actually.

Yes. always - I mostly write stories on the Sims and even when I don't actually write a story, I always have a story in my head for them. The ones I've been given as gifts always have backstories too...The link to some of my stories, and some of the gifts is here:
https://forums.thesims.com/en_US/discussion/920867/the-renovacy-challenge-a-new-and-short-challenge#latest
My game play is very linear, though sometimes my sims surprise me and develop parts of their personality that I hadn't expected at all.
This was a family and home that MamaD made for me and I wrote a story about it, and the characters definitely had a life of their own.
https://samelasstories.blogspot.com/2018/02/the-hutchins-and-mojica-renovacy.html
Link to the first chapter is above if anyone's interested...