Children of the Land — B.A. Chepaitis

Lord Aroc rules the world, giving the gift of immortality to those he chooses. But now a change is at hand, signaled by the dancing of the Northern Lights, when one young woman's choice to plant a small seed will determine world dominion.
That woman is Vareka, a Citizen working for Lord Aroc as a Watcher for the village of Eryahsa. Though both Citizens and Villagers are under Aroc's rule, only Citizens are given the gift of immortality. The villagers live apart from the City, and their lives end when the Servants of Aroc absorb them to feed the City's energy.
The balance between City and Village has been preserved for a long age, but now it is being unsettled. Heavy Solar Flares are disrupting the City's technology, and the resultant northern lights cause the villagers to recall ancient stories of the Dreamers - gods and spirit beings who would someday return. Then an old man in the Eryahsa tells Vareka that she is inheritor of a task that only she, daughter of a Dreamer and a human, can complete.
She bears a locket handed down from mother to daughter for ages uncounted, and the seed it holds must be planted , though none yet know where. If the Dream is to continue, Vareka must reclaim her past, and take her friends on a perilous journey to find the place and time of planting. As they make their way through ancient forests and ruined cities, they encounter terrifying enemies sent by Aroc to stop them. In the tunnels of Rondole they meet a stranger who rules the dead, and offers to lead them to the land of Okara, where Vareka must choose whether or not to plant the seed that will end Aroc's rule.