Masatora Obu trains horses at the Miho Training Center, maintaining a physically fit, strong, and athletic build that aligns with his hands-on methods despite his age. Raised in Hokkaido near Mukawa Town, he practiced Mongolian sumo in his youth, earning the champion title "Arslaan" through his physical prowess.

His strict training philosophy disregards bloodlines and emphasizes hard work to maximize each horse’s innate potential. He creates customized regimens, like specialized mud training for Midori Makibaō to overcome muddy-track weaknesses. These uncompromising "Spartan" methods sometimes risk horse health, leading some owners to avoid his services and reducing his stable’s size. Despite his stern exterior, he deeply cares for his trainees’ well-being and occasionally questions if his approach is too harsh.

Obu is the older brother of Midori Ranch owner Genjiro Obu. He has a daughter, Rika Kousaka, from a previous marriage; she jockeys Makibako. Though strict around her, he is intensely invested in her safety and racing success. He also assumes a fatherly role toward others, including Midori Makibaō and jockey Kansuke Yamamoto.

The anime adaptation incorporates comedic elements, such as Midori Makibao hitting him with a soccer ball or stealing his sushi, prompting humorous retaliation that contrasts his typically serious demeanor.

In the sequel "Taiyō no Makibaō," Obu forms a close partnership with Heishichiro Honda, and both advance to center chief roles. He trains the horse Femme Fatale, developing a fatherly bond with her. His legacy includes inspiring real-world horse training methodologies, with parallels drawn to techniques of renowned trainer Tamio Toyama.

Overseas assignments see him intensify regimens for international competitions. His past global travels, including to Mongolia, contribute to his multifaceted background and inform his rigorous approach to equine conditioning and race preparation.