Major Dan Dastun (later promoted to colonel in the second season) is the head of the Military Police. He is Roger's former commander, but they still maintain contact. Dastun resents having the force called the "watchdogs" of the Paradigm Corporation, and has expressed his disdain for its executives. He also knows that Alex Rosewater does not care about many of the residents.

Dastun's pride as a member of the military police puts him somewhat at odds with Roger after he resigns from the force, and he expresses an extreme amount of irritation every time Big O appears. At first this irritation is passed off as disliking the vigilante nature of the Megadeus. However, as the series progresses, he reveals to Roger that his irritation stems from the fact that the Military Police do not have the ability to protect the city adequately due to frequent Megadeus attacks. This requires Big O to step in fairly often to counter these attacks, which Dastun feels robs the military police of purpose. However, he comes to accept this during season 2. He is also one of the few characters who know of Roger's affiliation with Big O, and the only such character within the military police. He was revealed to have obtained this knowledge at some point before season 2, but is only seen directly discussing it with Roger once.