Yutaka Todoroki is a commander in the Mars Defense Forces, serving directly under Fleet Captain Kanki Akuh. He is an old friend of Akuh, sharing a long-standing relationship. Stationed at the Achilles Springs base, Todoroki becomes one of Akuh's closest subordinates when Akuh arrives to take command of a new ground navy battleship, working alongside Second Lieutenant Takeshi Hijikata. He joins Akuh and Hijikata on a tour of the vessel, where Chief Engineer J. Dalton discloses that the ship is secretly the repaired and refitted Aoba, Akuh's former flagship, now outfitted with experimental weaponry.