Koujiro Hachijima, known as Marcus Vance in some international adaptations, is a primary pilot in the resistance against the extraterrestrial invasion, operating the Mechander-2 aircraft as part of a larger combining mecha. His personality is defined by a pessimistic outlook and a hair-trigger temper, often leading to easy infuriation. This temperament originates from a profound personal loss—a loved one killed during the initial alien invasion—which serves as his core motivation for joining the combat forces. He shares a dynamic of vitriolic best buds with fellow pilot Jimmy Orion; both are hot-blooded and share a history of losing loved ones to the invaders, yet their personalities clash frequently. Kojiro is more rigid and mean-spirited, while Jimmy is generally more open and friendly, and their conflicting approaches have escalated to physical altercations, such as Kojiro striking Jimmy over actions that inadvertently harm the team. He functions as a skilled but cynical team member, whose interpersonal conflicts and deep-seated motivations shape his role in the narrative.