How do you feel about this topic?
For a character to be true to themselves, would simply
mean, they would not go against their nature to further
the story. In other words, we don't expect a doctor to
become someone who is also a master carpenter. Nor do
we expect a plumber to be able to perform brain surgery.
The characters in a story are true to themselves when
they fit the expectations of the reader and we are not
surprised by their behavior or abilities.
This may vary in situations where the particular scene
calls for our character to do something extraordinary or
out of character in order to overcome a crisis, or to
avoid personal harm. At times, the human spirit takes
us to another realm of endurance and our instinct for
survival comes in to play. In these situations, our
character may be expected to do things that we would
normal think impossible.
As for staying true to the story, a character is not
one-dimensional and is subject to the rules of continuity
on the belief that the story is a merely a guide into
places most people only dream about. As writers, we must
try to make our characters realistic so that their actions
are believable and true to the story.