Who is Patricio Aragones, the General's Double from The Autumn of the Patriarch and what is their importance?

Patricio Aragones is the General's double. The General discovers him impersonating him to make money. Rather than imprison the man, the General uses him as a double until his death. It is Patricio who is killed in an assassination attempt, which the General later admits was staged in order to find out who is loyal to the regime.