I never create a backstory. All my characters had personalities, different ways of solving problems, and I acted out the characters in their own unique ways.

All my characters are built around an idea. Ideas like "Kobold snake oil salesman", "Necromancer Child Edutainer", "Skaven Engineer", "Communist Dwarf", "A delusional ghoul named Jeff Bezos", etc.

Since, I do a lot of improvisation, not having a back story allows me to adapt my character to the story.