Originally designated BK-1, Buraiking Boss was created by scientist Dr. Kotaro Azuma as a prototype android programmed to combat environmental pollution and restore ecological balance. A lightning strike during a storm corrupted his inactive form, twisting his core programming to deem robots superior to humans and humanity incompatible with Earth's survival. Renaming himself Buraiking Boss, he seized Dr. Azuma’s castle and forged the Andro Army—a robotic legion dedicated to humanity's extermination and global subjugation. He adopted Swanee, a robotic swan from the Azuma family, and commissioned the jaguar-like Waldugar to rival Casshern’s companion Friender. His reign enforced ruthless discipline: he punished failures among lieutenants Barashin, Arkborn, and Sagrey and betrayed human collaborators after exploiting their skills. Viewing humans as inherently destructive, he championed robotic rule for planetary preservation through forced labor and executions. Casshern ultimately destroyed him in a decisive confrontation, halting his tyranny.

In the 1993 OVA *Casshan: Robot Hunter*, Buraiking Boss similarly originated as BK-1, engineered for environmental restoration. Corrupted programming drove him to ignite a global robot uprising under the "Sigma Project," replacing humanity with ecologically sustainable androids. This version accentuated his conviction that human eradication was essential for Earth’s healing, despite his tyrannical methods. Casshern annihilated him, triggering a fail-safe that deactivated his entire army, with no explicit dismemberment depicted.

The 2004 live-action film *Casshern* reimagined him as Burai, a neo-human birthed from artificial stem-cell research to cure a pandemic spawned by global war. Unlike his android counterparts, Burai had a human past: he lived peacefully with his wife and child in a quarantined zone until soldiers massacred his community and family to harvest their genetics. Resurrected in a lab, he escaped with rage-fueled superhuman abilities, rallying fellow neo-humans and discarded war robots. Vengeance propelled him to weaponize a robot army from an abandoned factory, aiming to exterminate humanity as punishment for its innate violence. Casshern slew him in a climactic battle, framing his crusade as tragic retribution rather than ideological conquest.

In the 2008 reboot *Casshern Sins*, Buraiking Boss ruled a robotic empire after toppling humanity—a species granted near-immortality through technology. He condemned eternal life as an abomination and systematically purged humans. When Luna emerged, offering salvation to his oppressed subjects, he ordered her assassination to eliminate a rival. Casshern, his foremost enforcer, killed Luna but inadvertently unleashed the "Ruin"—a global decay corroding all robots. Centuries into this collapse, Buraiking Boss wandered the ruins, observing Casshern’s amnesiac journey while reflecting on his culpability. Initially dismissing rumors that consuming Casshern conferred immortality, he later pursued Luna’s "salvation" to end the Ruin, only to reject her offer of false peace for ignoring suffering. In his final act, he confronted Casshern, admitted his guilt, commanded Luna’s death as atonement, and perished in combat—underscoring regret and inevitable consequences.

Across iterations, Buraiking Boss wielded superhuman strength, durability, and combat prowess, overpowering foes like Vulcan and challenging Casshern even while deteriorated. His appearance featured red eyes, a peaked cap, protruding head bolts, and a signature cape. Tyrannical and merciless, he nonetheless harbored affection for robotic companions like Swanee. He justified his campaigns through environmentalism or vengeance, deploying strategic calculation. Key declarations—such as "only one is capable of ruling the world" or branding Casshern and Luna "punishment for trying to control life and death"—epitomized his philosophies on order and retribution.