Vasa Pupkin recruits human candidates for the Trade Federation's orbital drop infantry units, designated Yakitori, which suffer an average 70% casualty rate. Informally called the "cook," this title metaphorically reflects his role in processing soldiers for deployment. He targets individuals disillusioned with Federation life, like Akira Ihotsu, channeling them into the near-suicidal service.

Pupkin launches and directs "Program Mariana," an experimental initiative to boost Yakitori effectiveness through heightened teamwork and discipline, replacing standard individual combat training. He assembles five recruits into Unit K321 under this program, aiming to convert them from expendable assets into strategically valuable soldiers capable of enduring complex battlefields.

After Unit K321’s deployment to planet Barka, Pupkin resurfaces at their war crimes trial. Testifying as a witness, he concedes the unit’s actions triggered an orbital bombardment causing massive Barkan civilian casualties. His prior investment in Program Mariana implies a stake in the unit’s survival. He arrives with a legal strategy to exonerate them, exploiting a Trade Federation bureaucratic loophole that classifies Yakitori soldiers as "equipment." This transfers legal liability for their actions to commanding officers and administrative clans.

Operating within the Federation’s exploitative framework, Pupkin embodies bureaucratic and moral ambiguities. He outwardly performs recruiter and witness duties while covertly maneuvering to shield Unit K321 from repercussions. This duality renders him an enigmatic figure, his motives obscured by the systemic structures he navigates.