Thief of Time - Creature of time

'Look, time has stopped, right?' said Lobsang.

'Yes.'

'So how can you be here talking to me?'

'I'm not what you might call a creature of time,' said Susan. 'I work in it, but I don't have to live there. There are a few of us about.'

'Like this Old Man Trouble you mentioned?'

'Right. And the Hogfather, the Tooth Fairy, the Sandman, people like that.’

***

The Thief of Time - p242