ONA
Description
Hideki Nogi is the chairman of the Nogi Group and becomes the 59th chairman of the Kengan Association following the events of the Kengan Annihilation Tournament. The Nogi Group is a powerful corporation with a long history in the Kengan matches, dating back to 1650, and holds an impressive record of victories. Nogi himself is an esteemed-looking, older gentleman with slicked-back black hair and wrinkled, experienced facial features, always seen wearing formal, high-quality attire.

Nogi's actions are driven by a centuries-old family debt. An ancestor of the Yamashita family, Yamashita Ichinoshin, was a fallen warrior but possessed an exceptional eye for fighting. He was hired by the head of the Nogi family and won many matches, though his body deteriorated as a result. This ancestor eventually died in the semifinals of a tournament to select the next Kengan Association president, which he entered to help his friend from the Nogi family achieve his dream of reforming the matches. Before he died, the Nogi family head left a will instructing future generations to find the Yamashita family and repay their sacrifice. For generations, the Nogi family was skeptical of this will, but Hideki Nogi discovered Kazuo Yamashita working at one of his subsidiary companies roughly five years before the main tournament, an encounter he felt was the fated moment his family had been waiting three hundred years for. This discovery inspired Nogi to plan to become the new Kengan Association chairman as a way to honor the debt.

Nogi possesses a shrewd, experienced, and cunning personality, with a sharp eye for identifying useful qualities in people and the skill to strategically exploit them for his own benefit. As a seasoned member of the Kengan Association, he has a perceptive understanding of the fighting environment, which allows him to analyze and predict the actions of fighters he observes. His cunning is formidable enough to outmaneuver powerful Association members like Hayami Katsumasa.

In the story, Nogi is the catalyst for the central events. He introduces the ordinary office worker Kazuo Yamashita to the violent world of underground Kengan matches and assigns him as the manager for the rogue fighter Tokita Ohma, whom Nogi had scouted. To give Ohma a path into the Kengan Annihilation Tournament, Nogi creates a shell company called Yamashita Trading Co., with Kazuo as its president and Ohma as its fighter. As a backup plan, he establishes another shell company, SF Cold Storage, with the fighter Rihito serving as both its president and fighter. Nogi himself has a close relationship with the legendary fighter Hatsumi Sen, initially intending for Sen to be the Nogi Group's primary representative in the tournament. Throughout the tournament, Nogi is a master strategist, employing tactics to manipulate other competitors and outcomes to improve his chances of winning the chairmanship, including hiring other fighters to target specific opponents. During the tournament, Nogi also reveals the history of the Yamashita and Nogi families to Kazuo, urging him to withdraw Ohma to prevent a repeat of Ichinoshin's sacrifice. Kazuo refuses, insisting that Ohma should be allowed to make his own choices.

Following Ohma's defeat in the tournament finals, Nogi is poised to face bankruptcy. However, the tournament winner, Takakaze Kirimi of Motorhead Motors, voluntarily yields the position, and Nogi is nominated to become the new chairman. In the sequel, Kengan Omega, Nogi faces new challenges as the chairman, including the Kengan Association's weakening cohesion and the threat of a rival underground gladiatorial organization, Purgatory. He is a key figure in negotiating a massive tournament to decide the terms of a merger between the two organizations to counter common threats like the Worm organization. Throughout this period, he grows closer to Kazuo Yamashita, mirroring the close friendship of their ancestors. In the face of new conspiracies and rebellious factions within the Association, Nogi continues to demonstrate his cunning, such as digging traps to catch the weaknesses of political rivals and collaborating closely with the powerful former chairman, Katahara Metsudo, to ensure the Association's survival.