Kate Barlow's character changes from a sweet teacher to a deadly outlaw.
In the beginning, Kate is cheerful and smiling. She gives Sam peaches in trade for onions and fixing the schoolhouse. She reads children poems and gives them an education, and her voice is like the sunshine.
Then, after Sam is killed, she goes a bit crazy and shoots the sheriff.
on top of all that, she becomes a wanted outlaw and murderer, dead or alive.
lastly, when Linda and Charles threaten to shoot her, she says she wants to be dead and commits suicide,using the bite of a yellow spotted lizard as her weapon.
this is how Kate changes from a kind woman to a fierce outlaw, or at least the way I picture it.