- Susan escaped from Gallifrey with her grandfather with little to no understanding of what was going on or why; Being technically no more than a very young child, she’s understandably rather traumatized by the whole ordeal
- Vicki’s mother died when she was young, and her father took a job on a colony planet. The ship carrying them to their new home crashed all the survivors barring Vicki were murdered, including her father.
- Steven grew up during a war in which he’d later fight; his ship crashed on a hostile planet were he was captured and kept as a prisoner for over two years with only a stuffed animal for company.
- Jamie was a piper who ended up fighting in a war.
- Victoria’s father was killed by the daleks
- Sarah Jane’s parents died in a car accident when she was young; she was raised by her aunt, who she’d later impersonate while working as a journalist.
- Tegan was on her way to start her job as an air stewardess when a series of unfortunate mistakes led to the murder of her aunt by the hands of the Master
- Nyssa’s planet was destroyed and her father taken over by the Master to be used as a new body
- Peri was a college student studying botany when she met the Doctor
- I’m not even going to go on about Ace that would take hours
I’m sorry but Rose isn’t the first companion to have a life