Dr. Kochin is the devoted assistant and right-hand man of the brilliant but reclusive Dr. Wheelo. A self-proclaimed expert in biotechnology, much of his personality is defined by an obsessive and single-minded devotion to his master's will. He embodies the archetype of the mad scientist, showing little regard for the ethical implications of his work and proving willing to endanger the world to achieve his goals. His primary motivation is to free his master from a fifty-year imprisonment inside an icy tomb and to procure a powerful new body for Dr. Wheelo's preserved brain, as he believes his master's genius should not be wasted.

At the start of the story, Dr. Kochin successfully gathers the seven Dragon Balls and wishes for Shenron to melt the ice entombing Dr. Wheelo's fortress. He then orchestrates the film's conflict by sending his creations to kidnap the fighters Master Roshi and Krillin, as well as the scientist Bulma. He also captures Piccolo and uses a mind-control device to turn the Namekian into a tool for his plans. From the control room of the fortress, Dr. Kochin commands his Bio-Warriors and manages the operation, revealing key exposition about Dr. Wheelo's past to the captives.

Dr. Kochin's most significant relationship is, of course, with his master, Dr. Wheelo. He serves Wheelo with unwavering loyalty, having saved his brain after his original body was destroyed and kept him alive for decades. He does not have any significant positive relationships with the heroes, viewing them only as obstacles or potential vessels for Dr. Wheelo. His connection to the wider world is one of scientific arrogance, seeing ordinary people and even powerful fighters as mere subjects for his and his master's experiments. Throughout the film, Dr. Kochin does not undergo any meaningful personal development or change of heart; his primary drive remains consistent until his accidental demise. One crucial revelation about his own nature occurs late in the story, when he is damaged and his outer skin tears away to reveal a fully mechanical, robotic endoskeleton. It is suggested he converted himself into an android, likely to extend his own life to serve his master.

Despite his aged and frail appearance, Dr. Kochin is equipped with several hidden abilities that make him a dangerous foe. He is capable of flight and can fire ki blasts for long-range attacks. His most distinctive weapons are concealed within his body: his left hand can transform into a rotary machine gun, and his serpent-headed cane can fire powerful energy blasts. As a scientist, his abilities are largely intellectual; his expertise in biotechnology allowed him and Dr. Wheelo to create powerful bio-warriors such as the Bio-Men and the three Brutal Warriors, Kishime, Misokatsun, and Ebifurya. He also developed the mind-control technology used to enslave Piccolo. Dr. Kochin meets his end not in a grand battle, but through an accident; as the giant body of Dr. Wheelo is activated, his master inadvertently knocks him from a high platform. He falls into an energy conduit and explodes, his robotic body unable to withstand the surge of power.