Prince Heinel, born to Boazanian crown prince La Gohl and noblewoman Lozaria, endured lifelong stigma as the traitor's son following his father's alleged betrayal of the empire. This heritage brought relentless bullying and humiliation from Boazanian nobility; only his maternal grandparents and later his childhood friend Katherine offered him genuine affection. Unaware of the truth, Heinel nurtured deep resentment towards his absent father while internalizing society's contempt. His father, La Gohl—a hornless Boazanian advocating equality—had been disgraced and imprisoned by Emperor Zu Zambajil.

Heinel pursued military excellence to overcome his tarnished name, graduating top cadet from the Boazanian Institute of Military Sciences and Warfare. His combat prowess earned him command of the Earth invasion force, though Emperor Zambajil secretly orchestrated this appointment, viewing Heinel as a threat and intending his elimination through battlefield failure or assassination. Heinel initially commanded with ruthless aggression, punishing subordinates like General Jangal and scientist Zuhl severely and employing brutal tactics against Earth, masking profound insecurity and shame about his lineage.

Throughout the invasion, Heinel's character evolved. While maintaining fierce nationalism and executing Zuhl for betrayal, he displayed emerging honor—sparing General Bergan after an assassination attempt and showing concern for loyal soldiers. His relationship with Katherine remained pivotal; she was his trusted confidante to whom he revealed past traumas, and he consistently prioritized her safety despite his merciless nature. Heinel's worldview shattered upon learning Kenichi, Daijiro, and Hiyoshi—leaders of the opposing Voltes Team—were his half-brothers through La Gohl's marriage to human scientist Mitsuyo Go. This coincided with revelations of Zambajil's tyranny and La Gohl's true motive: advocating slave rights, not treason.

Facing rebellion on Boazania, Heinel refused surrender even as his forces crumbled. After Katherine died shielding him from an assassin's gunshot, Heinel activated the ancient mecha Godol through a trial-by-fire ritual. In the final confrontation with Voltes V, recognizing his mother's dagger in Kentaro Go's possession, he fully accepted his familial ties. Heinel killed the fleeing Zambajil for hypocrisy and materialism. A dropped grenade triggered an explosion; in his last act, he saved Kenichi from the blast, choosing to remain in the flames despite his brothers' pleas, finding peace after acknowledging his misplaced vengeance and newfound kinship.