TV-Series
Description
Medama Oyaji is the father of Kitarō and a surviving member of the Ghost Tribe in the anime Hakaba Kitarō. Originally a fully formed adult, he was afflicted with a fatal disease known as the melting sickness. After his body decayed and he died, his soul took refuge in his own left eyeball, which then sprouted a tiny torso, arms, and legs, resulting in his iconic form: a miniature, anthropomorphic eyeball measuring approximately nine point nine centimetres in height and weighing about thirty-three grams. He is often seen bathing in a small teacup, a habit he maintains for cleanliness and, at times, to hide his tears.

In Hakaba Kitarō, Medama Oyaji possesses a harsher and more cynical temperament compared to his later, more comical portrayals. He can be short-tempered, prone to outbursts of anger, and is not afraid to express his disappointment or frustration, especially toward Kitarō when the boy acts irresponsibly. His love for his son, however, is unwavering and fierce, and his primary motivation is to protect Kitarō and ensure the survival of the Ghost Tribe. He is pragmatic, world-weary, and deeply aware of the dangers posed by humans and malevolent yōkai, which fuels his sometimes overprotective and anxious nature. He feels a strong responsibility to guide Kitarō, who is the last of their kind, and to uphold the tribe's legacy, even if his methods are blunt or severe.

His role in the story is that of a guardian, adviser, and moral touchstone for Kitarō. Medama Oyaji provides encyclopedic knowledge about yōkai, their habits, and their weaknesses, which he accumulated during his travels across the globe before Kitarō was born. He frequently acts as a strategist during conflicts, offering critical information and counsel that helps Kitarō overcome supernatural threats. Despite his tiny size, he is an active participant in many battles, often using his smallness to infiltrate enemies' bodies or hide in tight spaces. He can also call upon a mystical phantom train that allows travel through time, but using this power exacts a heavy toll on his life force.

The most pivotal relationship Medama Oyaji has is with his son, Kitarō. Their bond is central to the narrative; Medama Oyaji's existence is defined by his devotion to Kitarō, and he is willing to sacrifice everything for his child's wellbeing. He also interacts with Nezumi Otoko, toward whom he is frequently exasperated and dismissive, viewing him as a troublesome and untrustworthy nuisance. With Neko-Musume, he shares a more amicable connection, often supporting her and even regarding her as a suitable future wife for Kitarō. His relationship with the human Mizuki, who helps raise Kitarō after his parents' death, is one of cautious reliance and respect.

Medama Oyaji undergoes a subtle but clear development over the course of Hakaba Kitarō. He begins as a bitter, sarcastic remnant of a dying race, burdened by the tragedy of his own death and the precarious position of his son. As the series progresses, his protective instincts and paternal love become more pronounced, and he learns to trust Kitarō's judgment while still asserting his own authority. His sense of duty evolves from mere survival to actively shaping Kitarō into a capable defender of the balance between humans and yōkai. He also demonstrates a capacity for vulnerability, occasionally showing doubt and sadness about his own limitations and the harsh world they inhabit.

His notable abilities extend beyond his vast yōkai expertise and infiltration tactics. Medama Oyaji possesses extraordinary resilience: he can survive being flattened, burned, or crushed, eventually regenerating from damage. He can control his own size and flexibility to navigate confined spaces or act as a projectile. In extreme circumstances, he can summon the phantom train, a powerful time-travel device that can reverse events but drains his vitality severely. He also has the power to temporarily restore his original humanoid form, as seen when he briefly transforms to rescue Kitarō from a powerful foe, though this takes an immense toll on him. Despite his physical weakness and dependence on Kitarō, his sharp intellect, experience, and unyielding will make him a formidable ally and a crucial pillar of the Ghost Tribe's legacy.