My job is to gather all the legends and the knowledge of the planet and to make a book. Then, even when I return to the planet, the children may still be taught about many things...
If talked to after Bugenhagen's planetary display, but before the player reunites with the others around the bonfire, Hargo will tell player about the Promised Land. Hargo believes there is no one place called the Promised Land, but that doesn't mean the whole thing is a fairytale. He explains that the Promised Land doesn't exist for normal humans, but that it did for the Ancients, being their resting place.
The life of the Ancients was one of continuous journey to grow trees and plants, produce animals, and to raise Mako energy and the place they returned to after their journey, their burial land, is the Promised Land. Hargo explains that for the Ancients, the moment they were able to return to the Planet they were released from their fate, and gained their supreme happiness, which is why Promised Land is fabled as a place of paradisaical qualities.