This Wood Elf Ranger Backstory for the Lost Mine of Phandelver works well for the game if your DM doesn’t mind the idea of slavers. Feel free to use it and adapt it for your own character.
My mother and I lived in the woods at the foot of steep, snowy mountains. We had a handful of small shelters scattered about the woods and one or two caves that we would haul up in depending on the mission at the time. Mostly we would live off of the land and hunt for food.
My mother taught me that you never kill what you aren’t going to eat, you use every part and you help those in need. And that’s what we did. We would travel through the forest and help animals who were trapped. We would raise baby birds who had fallen out of the nest and we would help the local villagers to find edible plants. We would also help the older folks from the village by bringing back kills for them.
Sometimes we would travel closer to the larger town and earn some coin by doing odd jobs like tracking or selling fish.
One day my mother and I found disturbing tracks in the woods, there seemed to be some people in distress and they were put onto wagons. We tracked them and discovered that it was a group of Orcs, Half Orcs and men who were transporting a number of bound and badly beaten folks through the woods. We overheard them talking about the price they would get for them.
My mother told me they were slavers and that those people were kidnapped and going to be sold to the highest bidder.
We followed the wagons for three days through the woods waiting for an opportunity to help the people escape. It came one night when the guard on watch fell asleep and we were able to quietly release the people in the cages. They were starving and weak and could barely run but we helped them get away.
A week later my mother and I were back at one of our regular camps and I woke to shouts. Before I could even understand what was happening I was hit in the back of the head.
I came to eventually. I don’t know how long it was but my mother was gone. The tracks were the same as the slavers. They found us and took my mother, leaving me to die. I was badly injured and limped along trying to follow the path, wanting to save her. But I was weak and injured and I kept falling unconscious.
When I woke up again I was warm and cozy. I was by the side of a roaring fire and when I looked around I saw that I was in someone’s home.
A traveller had found me and brought me home, slowly nursing me back to health with weak broths poured slowly into my mouth and patting down my feverish head with cold cloths. If it hadn’t been for Gundren Rockseeker I don’t think I would have survived.
When I had recovered enough he helped me find work so that I could buy supplies and he asked me to help take some supplies up to Phandalin for him. I owed him and so I agreed, even though I just want to go after my mother.
Here’s what I do know about where my mother might be, she was taken by slavers. I remember something red, an emblem that was kind of round on the armour of one of the men who took her. They had wagons and distinctive boot tracks. The band was well organised and led by an Orc.
All I can do now is hope that the information I have is enough for me to go after my mother and find her while she is still alive.