Before founding Scar Chain, Nagi Kengamine was in a relationship with a fellow Deadman while imprisoned in G Ward. The two were expecting a child when they were forced to participate in a Carnival Corpse match against each other. Unwilling to harm his pregnant partner, Nagi intentionally lost the battle. However, his deliberate defeat resulted in a brutal Punishment Game, where he had his vocal cords removed.

As further retribution, Deadman Wonderland’s warden, Tsunenaga Tamaki, subjected Nagi’s wife to inhumane experiments, using her as a means to break him. This act of cruelty deeply scarred Nagi, yet he clung to hope, believing that his child had survived outside the prison. As a token of his lost love, he continues to wear his wife’s scarf around his waist.

Two years later, driven by his desire to one day reunite with his child, Nagi founded Scar Chain, a resistance group dedicated to opposing the corruption within Deadman Wonderland. He later appointed Karako Koshio as his second-in-command, entrusting her with a key role in the organization’s operations.

Nagi Kengamine was a young man with a frail and slender physique, often appearing weak due to the physical toll of his time in Deadman Wonderland. He had a gentle facial expression, which contrasted with his dark past. His long, curly dark brown hair framed his face, with strands covering his cheeks and a single lock falling between his brown eyes. A distinctive scar ran across his neck at the level of his vocal cords, a permanent mark from his Punishment Game.

Nagi’s usual attire consisted of a black sweater, light gray pants, and traditional geta sandals. One of his most recognizable features was the dark green scarf he wore at all times. Additionally, he kept a second, light brown scarf with a subtle motif tied around his waist, an item that once belonged to his late wife, serving as a reminder of his lost family.

During his descent into madness, Nagi’s demeanor changed drastically. His presence became far more menacing, and his eyes, once filled with warmth, lost both their pupils and irises, reflecting his fractured mental state.

Nagi Kengamine was a calm and composed leader, known for his kindness and unwavering dedication to his cause. As the head of Scar Chain, he sought to dismantle the corrupt system of Deadman Wonderland, not out of vengeance, but in pursuit of freedom his ultimate goal was to see his child and properly mourn his wife beneath the open, unpolluted sky. Unbeknownst to him, however, his unborn child had been killed during one of Tsunenaga Tamaki’s cruel experiments on his wife, making his dreams tragically unattainable.

A man of introspection, Nagi often used weather metaphors to describe situations, whether in battle, as seen during his fight with Hibana Daida, or while coordinating Scar Chain’s efforts, such as when manipulating Minatsuki Takami’s Penalty Game.

As his false hope unraveled, Nagi’s grief and frustration slowly consumed him, ultimately driving him to a state of insanity. He struggled with the realization that others were given the chance to live while his child never had that opportunity. Upon reaching his psychological breaking point, he deluded himself into believing that he was still sane, even as his actions became increasingly erratic and violent. Despite this, Nagi eventually managed to regain control over his mind and return to his former compassionate self.

In addition to his idealistic nature, Nagi had a personal preference for women with short hair, finding the style particularly attractive.

Enhanced Strength
In his enraged state, Nagi possesses immense physical strength, far surpassing that of an average human. He is capable of tearing bodies apart with his bare hands, lifting people off the ground effortlessly, and even crushing skulls with a single hand. His raw power makes him a formidable force in combat, particularly when driven by intense emotion or rage.

Branch of Sin
As a Deadman, Nagi has the ability to manipulate his blood outside of his body, a power known as the Branch of Sin.

Owl’s Eyeball (オウルズ・アイボウル, Ouruzu Aibouru)
Nagi’s Branch of Sin, Owl’s Eyeball, generates small, floating spheres enveloped in his blood. These orbs can be manipulated at a distance and remotely detonated at his command. Unlike many other Deadmen, Nagi’s ability does not require a direct connection to his blood vessels, allowing him to make use of even coagulated or previously shed blood. This grants him a strategic advantage in prolonged battles.

Radio Transmitter
To maintain covert communication, Nagi conceals a small transmitter within his teeth. The device can be extracted by opening his mouth and exposing an extendable antenna. He utilizes this transmitter to coordinate with Rokuro, modify Minatsuki Takami’s Penalty Game, and send distress signals when Scar Chain is betrayed.

Soundboard
Due to the loss of his vocal cords, Nagi’s mechanical voicebox is equipped with a soundboard capable of generating various sound effects. These include air horns, clapping, and even a rape whistle. However, after Genkaku hijacks its system, the device malfunctions, causing it to emit distorted moaning sounds, much to the shock and embarrassment of Karako Koshio.