Characters? Where do you get

the people you write about? I was asked that question yesterday by one of the Whirlwind's friends.
The Whirlwind and I looked at one another. We know precisely where one of the characters comes from. "Ruth" is "a little bit me, a little bit Cat and a little bit imaginary" in the Whirlwind's description. It was quite deliberate. It is what the Whirlwind wanted, what she asked me for. Nevertheless I had to wait for Ruth to appear. She took a while to come. When she finally did appear she was not quite the sort of person I thought she might be - and I had no choice.
The sources for the other characters are a great deal more complex than that - at least I think they are. The charscters seem to appear from nowhere. They tell me who they are. I have to listen. If I get it wrong then the writing does not work.
They name themselves too. Try to name them anything else and the character simply stops talking.
I do not normally write short stories. I have written very few of them. I have written three about "Tom" and "Lizzie" and "Mouse". Tom is a harp player with the Harpcottle Orchestra. Lizzie is his sister and Mouse is their cat. I have no idea at all where they came from. They just appeared. They have told me who they are and how they behave. I cannot change that.
I tried to explain this to the eleven year old asking the question. Next term they will do some writing exercises involving physical descriptions of people they know and that they create. It will tie in with biology, history, art and maths - and possibly other things. Their English teacher has already mentioned it to me.
But the question of where the characters come from is likely to remain a mystery. It irritates me but I am not sure I really want to know. It is better to be surprised.