Tetsuo Akiyama served as the founding captain of the Science Guard Party (Science Defense Squad), an elite Earth Defense Army Far East unit investigating mysterious phenomena and defending against monster threats. He personally formed the team after negotiating two specific conditions for accepting command: full authority to select members based on specialized expertise and exclusive operational use of the advanced aircraft Super Mardock.

His leadership blended calm observation with parental concern for subordinates, maintaining professional distance while showing care through actions like arranging a birthday cake delivery for team member Mutsumi Hoshikawa when he couldn't attend. Before commanding the Science Guard Party, Akiyama forged a close friendship with Ogawara, who later resigned to develop the independent anti-monster weapon system Hector.

Akiyama's command concluded in episode 26. Following the resolution of the Gibaruga monster incident, he received a promotion and reassignment to lead a monster observation team within the Earth Defense Army's United States branch. Captain Daisuke Gondo succeeded him, starting in episode 28.