She ends up unlocking some memories in Teddy about his role in the big massacre, and then she stabs them right out of him.
Of course, we got to watch in the finale when Teddy was the one who indeed killed Angela during the massacre as she begged to be saved.
Neither of those first two bits properly prepared audiences for her third appearance, for which she was feigning being a captive of Wyatt and his weirdo cult in order to fool Teddy and The Man in Black.
Later, Angela (or whatever name) was briefly seen in a straightforward flashback to the years before the park opened, where she was holding a white parasol and walking around Escalante.