The kaiju are a motif that represents nature and nuclear energy. Like nature and nuclear energy, the kaiju are powerful, dangerous, and difficult to control, though humans try to control and use them for their own interests. For example, Sanders explains that the kaiju’s reactors would be useful, saying, “Imagine the competitive advantage we could have if instead of building viable nuclear reactors, we could just grow them. Safe. Effective. Organic” (236). Sanders’s desire to use the kaiju for their reactors connects the kaiju to nuclear energy, both of which Sanders wants to use to make money and to become even more wealthy and powerful.

The kaiju motif serves all the novel’s major themes. In developing the theme of The Importance of Conservation and Environmental Stewardship, Scalzi traces Jamie and the other team members’ feelings about the kaiju as they develop from fear to respect and understanding. Sanders’s attempts to exploit Bella and the KPS’s mission to protect the kaiju emphasize theme of Humans’ Impact on Ecosystems. This illustrates both positive and negative human effects on Kaiju Earth. The kaiju’s volatile and dangerous nature also necessitates Teamwork and Community in the Face of Global Catastrophe.