Hiroaki Mishima serves as CEO of the defense corporation Altamira Agency, tasked with repelling extraterrestrial threats. He commands the organization deploying genetically engineered female pilots, designated "Wet Props" or "Battle Soles," who operate mechanized Skelter units. Mishima operates with a results-oriented leadership style, prioritizing mission success and operational efficiency above all other considerations.

After the initial battle against an alien entity in Tokyo, Mishima critically assesses the outcome. Despite the successful elimination of the threat, he judges the commanding officer, Otsuya Funagai, a failure due to excessive collateral damage and the near-destruction of the Skelters. This decision reflects Mishima's utilitarian philosophy and intolerance for perceived operational inefficiency or emotional compromise. His judgment emphasizes corporate interests and tactical pragmatism over individual pilot welfare or commander sentiment.

Mishima embodies corporate authority focused on organizational discipline. He exhibits no personal investment in the artificial soldiers beyond their functionality as military assets. His interactions enforce a strict hierarchy where operational failures receive immediate censure without consideration of mitigating circumstances. His role remains confined to his executive position within the Altamira Agency's command structure, with no expansion of his background, personal history, or development beyond this function.