Mark Crutchfield is a minor character in his own fictitious autobiography, "I Didn't Ask To Be Born!" which he hasn't written yet. Philosophers, scientists and librarians are trying to explain how this is possible, so Mark's belligerence has turned out to be a virtue in the face of repeated claims that he shouldn't exist.
Mark knows how the autobiography turns out (spoiler alert: death), but he struggles on anyway so that he'll have a life story to tell at the end of it.

Distracted by trying to earn a living as a mental health and forensic support worker, a police constable, a mountain sport instructor and, amongst many other roles, an ambulance driver, Mark struggles to find time to write. 'Earthwork', his first novel, took him eighteen minutes. His second, 'Walk With Kings', took even longer. By the time he had recovered sufficiently to write 'The Last Best Gift', he had to spend a whole hour of his life sitting at a desk. He's now worried about how he'll find time to write a fourth - even whether or not he should, since rumour began to spread about the strange effect that his books have upon their readers. Legend has it that if you sit indoors alone on a dark and stormy night, light a single candle and attempt to read a Crutchfield novel, you'll fall asleep...

https://www.amazon.co.uk/Mark-Crutchfield/e/B00U2V5UP2/