TV-Series
Description
Lt. Gem Starbuck is the English-language name for Ai Tachibana, one of the two main protagonists in the 1977 anime series Kyōryū Daisensō Aizenborg. She is the sister of Zen Tachibana, known in the English version as Capt. Jim Starbuck. Both siblings were originally ordinary humans who suffered a catastrophic accident that left them critically injured. To save their lives and enable them to continue fighting the reborn dinosaur menace, they were fitted with extensive cybernetic implants, becoming cyborgs. This transformation integrated them into the D Force or Gemini Command, the elite defense unit formed to battle the intelligent dinosaurs and their leaders.

In terms of personality, Lt. Gem Starbuck is portrayed as determined, compassionate, and fiercely protective of her brother and the human race. She exhibits a quiet strength and a willingness to sacrifice her own safety for the greater good. Her motivation is rooted in the desire to defend Earth from the intelligent dinosaurs that have returned to reclaim the surface, as well as to protect her brother, with whom she shares an exceptionally close bond. This sibling relationship is the emotional core of the series; the two characters rely on each other completely, and their cooperation is essential for their combined fighting forms.

Her role in the story is that of a key operative within D Force. She pilots the support vehicle Izen II and, together with her brother, performs the fusion technique known as the Izen Cross or Gemini Transfer. During this process, their life essences and cybernetic systems merge, creating a single powerful entity. In the early part of the series, this fusion results in the combat form Izenborg Man, while their vehicle transforms into the Izenborg-Go. Later, after a near-fatal battle that leaves her severely damaged, a restorative procedure accidentally gives her enhanced superhuman abilities, including telekinesis and greatly increased strength. This allows the siblings to further combine with the vehicle into the giant hero known as Izenbo, broadening their capabilities against larger foes.

In terms of development, Lt. Gem Starbuck evolves from a capable but physically limited cyborg into a being with extraordinary psychic powers. The trauma she endures and the subsequent transformation deepen her resolve and expand her role from a pilot and fusion component to a more independent source of power. She also occasionally acts as the central mind within the combined form, directing the giant hero's actions.

Her notable abilities include heightened physical strength and resilience due to her cybernetic enhancements, the capacity to synchronize with her brother for the fusion, and later the possession of psychic powers such as telekinesis and energy projection. These powers enable her to contribute offensively and defensively in battle, whether as a separate combatant or as part of the merged entity. Throughout the series, she remains a loyal, courageous, and indispensable member of the team, standing alongside her brother and the rest of D Force against the ever-adapting dinosaur army.