Movie
Description
Medama Oyaji is the father of Kitaro and a member of the Ghost Tribe, the ancient race that once dominated the earth. In his original form, he was a fully grown man, but he succumbed to a terrible disease known as the melting disease, which caused his body to decay. Following his death, his spirit and consciousness relocated to his left eyeball, which grew a tiny body and limbs, allowing him to return to life in his iconic diminutive form as a living eyeball. This transformation was driven by his intense concern for his unborn son, Kitaro, who was born from his mother's grave after both parents had died. In the film Kitarō Tanjō: Gegege no Nazo Shinsei-ban, his past is explored in depth, showing him as a humanoid man with white hair and a calm, composed demeanor before his transformation. During this period, he is searching for his missing wife and travels to the village of Nagura, where he meets a man named Mizuki.

Personality-wise, Medama Oyaji is deeply intelligent and possesses extensive knowledge of yokai from all over the world, having traveled widely before Kitaro's birth. He is a calm and rational figure in most situations, often providing guidance and wisdom to his son and their allies. Despite his small size, he has a strong spirit and a great love for his son, frequently worrying about Kitaro's safety and well-being. He can be overprotective and doting, sometimes to a comical degree, but he also shows a strict and disciplined side when teaching Kitaro lessons about responsibility and the proper conduct expected of a member of the Ghost Tribe. He enjoys taking hot baths in a teacup, which is a signature habit, and he has a fondness for cherries and other small foods. In his earlier, humanoid form in the film, he is portrayed as a reserved, stoic individual who initially keeps his distance from humans due to past persecution, but he gradually opens up to others, showing a warm and emotional side, especially when it comes to his family.

His primary motivation is the protection and nurturing of his son, Kitaro. He is driven by a father's love and a desire to see his son thrive in a world where both humans and yokai can coexist. In the film, his immediate goal is to find his wife, which leads him into a dangerous conspiracy involving a powerful family and a mysterious blood-based drug. His ultimate motivation is to secure a future for his child, even if it costs him his own life.

In the story, Medama Oyaji serves as a mentor, guide, and moral compass for Kitaro. He often accompanies his son on adventures, riding in Kitaro's hair or on his shoulder, offering advice and using his vast knowledge to identify enemies and solve problems. In the film, he is one of the two main protagonists alongside Mizuki, and his actions set the stage for Kitaro's eventual birth and his own transformation into the eye-like form. He plays a crucial role in uncovering the dark secrets of Nagura village and makes a great sacrifice to contain a massive accumulation of grudges, allowing his wife and child to escape.

His key relationships include his son, Kitaro, whom he loves unconditionally and for whom he would sacrifice anything. He shares a deep bond with Kitaro's mother, whom he cherishes and searches for desperately. The film also develops his relationship with Mizuki, starting as a tense and distrustful encounter between a human and a yokai, but evolving into a deep friendship built on mutual respect and shared goals. He has a strained relationship with Nezumi Otoko, whom he often finds annoying and untrustworthy. He is also acquainted with many other yokai, including Sunakake Baba and Neko Musume, who respect him as an elder.

Throughout the series, Medama Oyaji's character development is largely static in terms of his core traits, but the film provides significant development by showing his past. He transitions from a silent, wandering husband searching for his wife into a loving, self-sacrificing father who chooses to give up his human-like form to become a small, enduring spirit that can watch over his son forever. This backstory adds depth and emotional weight to his later, more comedic appearances.

Notable abilities include his extraordinary resilience; he can survive being flattened, fried, or having his eye crushed, recovering after a short period. He is a master of infiltration, using his tiny size to enter enemy bodies and attack from within, clogging organs, or forcing them to surrender. He can summon the Phantom Train, a mystical vehicle that allows passengers to travel through time, though using this power severely drains his life force. He also possesses a wide array of knowledge about yokai, magic, and history, which makes him an invaluable advisor. In some adaptations, he can temporarily revert to his original human-like form to fight more effectively. His intelligence and experience are his greatest weapons, often allowing him to solve problems that brute force cannot.