Marna was a character in a brainwashing scenario created by the Vori to convince Chakotay to hate their enemy the Kradin and fight for them. She was part of a village that helped Chakotay when he was wounded in battle. She called him a glorious defender and offered him food and shelter.
When he asked for a way to communicate with USS Voyager, she told him that the Kradin had taken away all their machines. Later when Chakotay returned to the village, he saw that it had been captured by the Kradin, and Marna told him that the Kradin were taking the old and ill villagers to be exterminated. This was all an illusion. (VOY: "Nemesis")