With its focus on the perilous world of international espionage, Stormbreaker makes use of plenty of stereotypes from spy films and popular culture. One of the best examples of this is Nadia Vole, who's characterized mostly through post-World War 2 German stereotypes.
Like many a Bond villain, Vole's nationality plays a big role in her identity. She's cold, calculating, and unemotional, and she seems to enjoy hurting others, closely monitoring Alex's jellyfish fight because she "wanted to watch him die" (14.24). She's tricky, ready to double or triple-cross you at a moment's notice.
These are all stereotypes of German culture, made especially popular in the aftermath of World War II. We can see something similar with Yassen Gregorovich—his business-like demeanor is reflective of Russian stereotypes rooted in the Cold War. While neither of these conflicts directly play into the plot of Stormbreaker, their influence on its characters is hard to deny.