Resolving differences between competing groups is a major theme of the book, evident even in the layout of the chapters. Until Chapter 22, Alek and Deryn alternate chapters as their respective countries move toward war. In a way, Alek and Deryn are competing for the reader’s attention, just as their countries are competing for resources and victory. The chapters slowly bring the characters together until they are face to face and interact as people, not enemies. The friendship between Alek and Deryn bridges the gap, allowing the crews of the Leviathan and the stormwalker to communicate with and help one another.

The relationship between the Darwinists and Clankers begins because Alek wants to help the shipwrecked people. After he gets captured, the Darwinists and Clankers only work together because each group has something the other needs: The Darwinists need the food stores from the castle, and the Clankers need Alek. After the Germans attack the Leviathan while Volger is a hostage and Alek wrecks the walker, the Darwinists and Clankers become even more dependent on one another. Without working together, both groups would starve and freeze on the glacier—if they weren’t captured and killed by the Germans first.

Though they are born from necessity, the relationships between Alek, Deryn, and Dr.