In the anime Endride, the character referred to as Dad Asanaga is Kazunobu Asanaga. He is the adoptive father of the protagonist, Shun Asanaga, and a figure whose actions serve as a primary catalyst for the series' central conflicts.

Kazunobu is a scientist and a businessman from the surface world. Possessing a highly analytical and calculating mind, he is driven by a deep-seated ambition to gain recognition within the scientific community and build a prosperous enterprise. His motivations are complex, intertwining a genuine, albeit twisted, love for his family with a ruthless determination to achieve his goals at any cost. Initially struggling for acknowledgment, his discovery of the underground world of Endora presents an opportunity he is unwilling to let pass. He becomes fascinated by Endora's Warp Particles and Warp Relics, seeing them as the key to his success on the surface.

A master manipulator, Kazunobu uses his knowledge of surface technology to entice Alzerm, the king of Endora and Emilio's biological father, with promises of a brighter future. He falsely claims that by helping transfer Warp Particles to the surface, he can restore Endora's ruins of Babel in return. In truth, his sole aim is to acquire the Warp Particles for his own study and benefit. When Alzerm discovers the betrayal, Kazunobu coldly murders him to obtain a sample of his body and further his research into creating his own Warp Relic.

Kazunobu's most defining and personal action involves Shun. Shun is actually the biological son of Delzaine, the current king of Endora, and was gravely ill as an infant. Entrusting his son to the scientist from the surface in the desperate hope of saving his life, Delzaine gave Kazunobu the child. However, Kazunobu, whose own wife had suffered a stillbirth, made the conscious decision to keep Shun. He raised the boy on the surface as his own son, effectively kidnapping him and filling the void left by the loss of his biological child. Kazunobu truly considers Shun his precious son, yet this love is fundamentally possessive and built on a foundation of deceit and theft.

Throughout the story, Kazunobu acts as an antagonist, though his role is that of a shadowy, distant orchestrator whose past machinations directly shape the present. His relationship with Shun is the emotional core of his character. He reveals that his work with the Warp Particles funded the medical treatment that saved the young Shun's life, attempting to justify his exploitation of Endora as a means to an end for his family's survival. When Shun learns the truth about his origins and his father's manipulation and murder of Alzerm, he cannot agree with Kazunobu's plans. In response, Kazunobu coldly warns his adopted son not to interfere, threatening to kill him if necessary. Despite this, Shun struggles to reconcile this harsh reality with the loving father who raised him, and he continues to hold affection for the parents he knew.

Kazunobu is not a warrior and does not possess an inborn Warp Relic like the inhabitants of Endora. His abilities are intellectual and technological. His primary tools are his scientific genius, his understanding of the crystals that connect the two worlds, and the conventional weapon of a gun, which he uses to kill King Alzerm. Unlike the noble characters who fight with magical relics, Kazunobu represents the intrusive power of modern, ruthless ambition. In the end, his schemes catch up with him as Emilio, seeking vengeance for his father's murder, tracks him down and kills him at the ruins of Tir na Nog. His death marks the end of his direct influence, but the consequences of his actions—the complicated family ties between Shun, Emilio, and Delzaine—remain the driving force of the narrative.