Yohei Onuma, grandfather to Shizu Onuma, served the Makishima family faithfully for many years. Following the death of Agito Makishima's parents, he continued his devoted service to the young heir, developing a profound, almost paternal concern for Agito's welfare. His loyalty to the Makishima household endured across generations. Yohei harbored deep anxiety for Agito's safety throughout the conflict with the Chronos organization. This protective instinct reached its peak when Agito, as Guyver III, faced an assault by the Hyper Zoanoid Enzyme III. Without hesitation, Yohei threw himself in front of Agito to protect him. Instantly impaled, he died in this final act of sacrifice, underscoring his unwavering devotion to the Makishima family.