Nat

Nat is caring, cautious and more openly concerned about danger than Riko. He understands her fascination with the Abyss but does not share her willingness to abandon everything on the surface for it.

His concern can make him argumentative, particularly when Riko makes decisions he considers reckless. He struggles to say directly how much he will miss her and initially expresses those feelings through opposition and frustration.

Nat also has a strong sense of responsibility toward other disadvantaged children. His long-term ambition is not simply to advance as a delver but to create an orphanage in the Wharf Quarter, the impoverished district where he once lived.

Nat is a Red Whistle and has completed the initial training required of apprentice cave raiders. He understands basic delving procedure, Abyssal hazards and the practical skills taught at the Belchero Orphanage.

His current rank limits how deeply he can legally descend, and he has not demonstrated the exceptional combat abilities or specialized Relics associated with more experienced cave raiders.

Nat's strengths are primarily practical. He knows Orth well, assists his friends with their plans and understands enough about cave raiding to recognize how dangerous Riko's intended journey will be.

Nat is part of Riko's everyday life before her Last Dive. He trains alongside her at the orphanage and becomes involved when she and Shiggy hide Reg and investigate the mysterious robot.

When Riko decides to leave Orth, Nat strongly opposes the plan before ultimately helping her prepare. His reaction emphasizes the permanent cost of her decision: descending into the Abyss means leaving behind people who genuinely expect never to see her again.

Later surface-side material follows Nat and Shiggy as they investigate strange developments in Orth, including the Birthday-Death Disease and events affecting Kiyui.

Riko is one of Nat's closest childhood friends. He strongly opposes her Last Dive because he understands that it will permanently separate her from everyone in Orth, but he ultimately helps with her departure.

Shiggy is Nat's fellow orphan and frequent companion, both before and after Riko leaves the surface.

Jiruo is Nat's instructor and the Moon Whistle whose rank Nat hopes eventually to attain.

Reg is initially hidden at the orphanage with Nat's help after Riko brings him home.

Kiyui is one of the younger children at the orphanage whom Nat helps look after.

Laffi is a familiar adult whose shop Nat and the other orphans frequently visit.

Hablog is another trusted adult in Nat's life and regularly tells the orphanage children stories about the Abyss.