Dr. Tokioka, also known later as Dr. T, is a scientist whose work is central to the events surrounding the resurrection of Brandon Heat. His early career placed him in a laboratory owned by the Millennion organization, but this period of research was violently interrupted by an attack from a thug named Mad Dog Ladd. The assault resulted in the death of all of Tokioka's colleagues, while Tokioka himself was taken hostage along with his research files. This traumatic event forced him to continue his work under duress for a different master.

In the years that followed, Tokioka became a key figure in the development of a process known as necrolization, a technology capable of regenerating and reanimating the dead. He was later seen, reluctantly, demonstrating the results of this process to other criminal elements, observing in grim horror as living subjects were prepared to become the first test samples. His research, born from coercion, would ultimately define his life and burden him with immense guilt.

Dr. Tokioka is characterized as a pensive and deeply remorseful individual. Despite his genius-level intellect and his pivotal role in creating the technology for necrolization, he is not a stereotypical mad scientist driven by ambition or a lust for power. Instead, he is a man haunted by his own actions, viewing his scientific achievements as an unforgivable sin. This overwhelming guilt leads him to eventually reject his own surname, referring to himself simply as Dr. T as a form of penance for the crimes he feels he has committed by bringing the dead back to a horrifying semblance of life. Beneath this layer of remorse, however, he possesses a genuine streak of kindness, which becomes evident in his role as a caretaker and ally.

His primary motivation shifts from scientific inquiry to a desperate need for atonement. After being coerced to continue his necrolization research under Harry McDowell’s rule, he foresaw the danger of creating an army of mindless deadmen. As an act of defiance and an attempt to right his wrongs, he used his own technology to resurrect the corpse of Brandon Heat, transforming him into the being known as Beyond the Grave. His goal was not to create a tool for Millennion, but to unleash the one person capable of stopping the rampant misuse of necrolization and ending Harry’s tyrannical reign. He dedicated the remainder of his life to supporting this mission.

In the story, Dr. Tokioka serves as the crucial support system and sole ally for Grave. He operates from a mobile base, typically an armored truck, which is specially equipped with the life-support machinery necessary to sustain Grave's reanimated body. His role is that of mission control, mechanic, and medic, as he is responsible for regularly replacing Grave's blood, maintaining his weapons, and repairing his body after battles. Beyond his relationship with Grave, he becomes the guardian and caretaker of a young girl named Mika Asagi, dedicating himself to keeping her safe from the warring factions.

Key relationships define his journey. His most significant bond is with Brandon Heat, whom he refers to as Grave. He was the one who answered Brandon’s request to be necrolized should he die, and he becomes the one person Brandon trusts to aid in his final mission. He also has a notable relationship with his unnamed twin brother, who serves as the loyal butler to Millennion’s leader, Big Daddy. Dr. Tokioka uses this family connection to secretly deliver a final letter and a pair of custom pistols, the Cerberus, from Brandon to Big Daddy. His relationship with Harry McDowell is one of a coerced employee and, eventually, a rebel working to overthrow him.

Dr. Tokioka undergoes a clear moral and psychological development. He begins as a scientist caught in a web of violent coercion, forced to develop horrific technology. Over time, he transforms into a willful agent of atonement, actively defying those who would use his work for evil. His final act of rejecting his own name to become Dr. T symbolizes his complete rejection of his former self and his acceptance of a new identity defined by guilt and a singular purpose.

His notable abilities lie not in combat, but in his scientific genius. He is the brilliant but tormented mind behind the necrolization process. He also demonstrates considerable engineering skill, as he is responsible for designing, building, and maintaining the complex weapons and life-support systems that Grave relies on. This includes the anti-Superior bullets specifically engineered to defeat the most powerful of the necrolized beings. In his final moments, Dr. T uses his medical knowledge to perform one last blood transfer, sustaining Grave for an additional ten days even as he dies from a mortal wound sustained while shielding Mika from an attack.