TV-Series
Description
Gyumao, also known as the Ox-King, is a character who appears early in the Dragon Ball story as a formidable and infamous figure. He lives in a large castle perched atop Fry-Pan Mountain, where he is rumored to be extremely frightening and has earned the title of Demon King for stealing gold and treasure from the surrounding lands. Despite this fearsome reputation, his true nature is far more nuanced, and he is revealed to be quite harmless and fun-loving at heart. His very name and concept are drawn from a character in the classic Chinese novel Journey to the West, specifically the Ox-Demon-King.

Gyumao is introduced under challenging circumstances. While on a picnic with his only daughter, Chichi, his castle and the entire Fry-Pan Mountain became engulfed in a massive, inextinguishable inferno, preventing him from returning home. In his search for a solution, he seeks out his old master, the renowned martial arts hermit Muten Roshi, hoping to borrow the Bashosen, a legendary fan said to have the power to put out any fire. During this quest, he encounters the young Son Goku, recognizing the Power Pole on his back and learning with great excitement that Goku is the grandson of his former training partner, Grandpa Gohan.

This connection reveals a crucial part of Gyumao's background. He is a former disciple of Muten Roshi, having trained alongside Grandpa Gohan, who was the master's first student. This martial arts pedigree explains his considerable strength. Even though he has turned to a life of banditry, he still holds deep respect for his old master, kneeling and apologizing when scolded by him for his misdeeds. After Roshi extinguishes the fire on Fry-Pan Mountain with a Kamehameha wave, Gyumao is so grateful that he invites his master to come and live with his family.

The most significant turning point in Gyumao's life comes when Goku marries his daughter, Chichi. From this moment on, his role in the story transforms completely. The once-fearsome bandit king evolves into a kind and gentle grandfather, often seen dressed in casual clothes. He becomes a supportive patriarch for the growing Son family. He helps to calm the quick-tempered Chichi, who often worries about her husband Goku and son Gohan during their absences on perilous journeys, such as the trip to Planet Namek and the tense days leading up to the Cell Games.

His role, while diminished compared to the main fighters, remains one of steadfast support. He is never far from his family, cheering for his great-granddaughter Pan at the 28th Tenkaichi Budokai. In the face of the ultimate threat, the evil Majin Buu, Gyumao joins the cause by lending his energy to help form the massive Genki-Dama, or Spirit Bomb, that Goku uses to finally defeat the villain. His financial support is also a key part of the family's life, as Chichi mentions that the money her father left them is what the family lives on for many years.

In terms of abilities, Gyumao is a formidable martial artist thanks to his training under Muten Roshi. He possesses immense physical strength, appropriate for a man of his size and reputation as a bandit king. As a direct student of Roshi, he is also a skilled user of the Kamehameha wave, having learned the technique from his master. While his fighting prowess is rarely showcased in the later parts of the story, his early presence establishes him as a powerful figure in the world. His character arc is a clear journey from a terrifying demon king to a loving father and grandfather, showing that his fearsome reputation was largely built on rumor and his own past misdeeds, which he ultimately leaves behind to become a gentle and caring member of the Son family circle.