Tree

Tree is a young woman only a little older than Rin. She resides in the sunken marketplace along with the rest of her tribe, the Roll-Scrapes.

When Shasta and Rin first enter the sunken marketplace, Tree attempts to waylay them, but quickly finds Shasta a more apt combatant. After Tree leaves the pair and rejoins the rest of the Roll-Scrapes, she returns and pledges to accompany Shasta on her search of the marketplace, risking the ire of the Drill-Kills in doing so.

According to Tree, her mother was from the surface.