TV-Series
Description
Kouhei Nikaidou is a private first class in the Imperial Japanese Army’s 7th Division and the older identical twin brother of Youhei Nikaidou. He operates as a loyal subordinate to Lieutenant Tokushirou Tsurumi during the hunt for hidden Ainu gold. Physically, he shares his brother’s sharply defined features, with a thin, pointed nose, black eyes, and black hair typically worn in a style that keeps it off the collar.

His personality is defined by an intense and volatile fixation on vengeance. After the death of Youhei at the hands of Saichi Sugimoto, Kouhei’s entire being becomes consumed by the need to kill Sugimoto, a fixation that overrides almost every other consideration. He is aggressive, spiteful, and prone to reckless outbursts, yet he demonstrates a stubborn resilience that keeps him in pursuit even as his body is steadily wrecked.

Throughout the story, Kouhei suffers catastrophic injuries that leave him as a diminished but relentless figure. He loses both ears, his left arm, and his right leg, necessitating the use of crude prosthetic replacements for the missing limbs. These losses do not temper his resolve; instead, they amplify his haunting presence, turning him into a grim spectacle of obsessive hatred. His physical deterioration mirrors his psychological unraveling, yet he continues to serve the 7th Division’s interests when they align with his personal vendetta.

His relationship with his twin defines him. Youhei’s death creates a void that Kouhei fills only with the promise of revenge. While Kouhei initially appears alongside his brother as a coordinated threat, his later appearances are solitary and marked by a raw desperation. Within the 7th Division, he interacts with figures such as Tsurumi and the loyalist soldier Usami, often acting as a violent tool for their schemes, though his own agenda always lurks just beneath the surface.

Kouhei’s role in the narrative is that of a persistent secondary antagonist whose path collides with Sugimoto’s group at multiple points. He begins as one half of a twin pair ambushing Sugimoto in a soba shop and later returns as a broken phantom, attacking when the opportunity arises. His development traces a downward spiral: from a composed soldier to a mutilated avenger who can no longer experience anything beyond the need to inflict pain on the object of his hatred.

Despite his mangled state, Kouhei remains a combative threat. He adapts to his prosthetics and exploits moments of chaos to strike, proving that his military training and sheer will have not been dulled by his injuries. His endurance and ability to keep fighting after horrific wounds make him a particularly unsettling presence among the many broken souls drawn into the gold hunt.