Pyoro is a small navigation robot, referred to as a NAVI robot or navibot, that originally served aboard the Taraak colony ship Ikazuchi. It was part of the ship's systems as far back as the era of the original colonization mission, which makes it one of the oldest pieces of equipment connected to the vessel's history. When the upgraded Ikazuchi was boarded and Hibiki Tokai was taken into custody, Pyoro was assigned to guard him while he was held behind an electronic barrier. After the Ikazuchi merged with the pirate vessel to become the Nirvana, Pyoro remained aboard and gradually became a familiar presence among the crew, appearing as a supporting character throughout the events of Vandread: The Second Stage.

Pyoro was originally an ordinary machine without a distinct identity, but an intense electric shock overloaded its systems and triggered self-awareness. From that point, Pyoro began spontaneously saying its own name, often even when it was not part of a conversation. It developed behaviours that suggested genuine emotion, curiosity, and a strong sense of attachment to the ship and its people. It is frequently found near Hibiki or near Parfet Balblair, and one of its notable traits is a sensitive emotional link to the Nirvana itself: when something is wrong with the ship, Pyoro behaves as if it is sick, giving the crew an early sign that a system or situation has gone wrong.

Pyoro's motivations are not expressed through grand goals or speeches but through its actions. It seeks company, shows devotion to the crew, and demonstrates a persistent desire to understand and care for others. This is most visible in its reaction to the pregnancy of Ezra Vieil. When Ezra's condition was discovered, Pyoro became intensely curious about babies and about how human beings are born. After Ezra gave birth to a daughter, Pyoro took on the role of nanny and insisted that everyone call the child Pyoro2, even though Ezra had already named her Calua. That episode reflects both the robot's earnest, single-minded nature and its wish to be treated as part of the ship's extended family.

In the story, Pyoro acts as a companion, a helper, and a quiet source of continuity aboard the Nirvana. It performs its original navigation duties and is also used by Parfet as a conduit for the Praksis energies, a function that connects the robot directly to the mysterious power that drives the ship. Pyoro's most significant role during combat comes in the Nirvana's second battle with a harvester mothership, when it becomes the core of a powerful combined formation called Super Vandread, also known as Vanfread Pyoro. In that form, Pyoro is integrated into the Vandread unit and becomes central to the ship's fighting ability at a crucial moment.

Pyoro's relationships develop noticeably over time. Its connection to Hibiki moves from that of a guard to that of a constant companion, and it is often seen near him during daily life aboard the ship. Its bond with Parfet is practical as well as warm, since she uses Pyoro as a conduit for the Praksis energies. Its relationship with Ezra deepens through curiosity and caretaking, culminating in its self-appointed role as nanny to Calua. These connections trace the robot's development from a simple piece of equipment into a self-aware individual with its own loyalties, habits, and sense of responsibility.

Pyoro's notable abilities include its original navigation functions, its capacity for self-awareness and simple speech, and its empathic connection to the ship, which lets its behaviour reflect the condition of the Nirvana. It can also serve as a conduit for Praksis energy in cooperation with Parfet, and it can act as the core of Super Vandread, a role that ties its own systems directly into the battle unit. Through these abilities and its growing bonds with the crew, Pyoro moves from being a background piece of machinery to an accepted and valued member of the ship's company.