Dr. Kochin

Dr. Kochin was Dr. Wheelo's assistant and right hand man, they were once scientists working on an expirament to make Dr. Wheelo into the most powerful fighter when suddenly a blizzard occured and caused a cave in and Dr. Wheelo was killed, he preserved his brain in a tank, after some time old age caught up to him and he had his creations put his brain inside of an android replica of his body, some time later he gathered the dragonballs and summoned Shenron to thaw out the cave which was encased in ice.

He had previously heard of Master Roshi who at the time of the cave in was the most powerful fighter in the world so he sent some Bio-Men and some of his most powerful creations Mikatsun, Ebifurya, and Kishime after him, Roshi defeated the Bio-Men but was defeated by the others, he later learns from him that Goku has surpassed him in power and tries to steal his body, after a lenthy battle Goku destroys Mikatsun, Ebifurya, and Kishime.

Some time later he reveals that he has captured Piccolo and is using him as a tool to kill the others with by use of a mind controlling headband, eventually Gohan is able to destroy the device and revert him back to normal, by this time Dr. Kochin personally attacks them using a cane that fires energy blasts and a machine gun arm, Krillen broke the cane and Master Roshi karate chopped his arm off, having no other choice he puts Dr. Wheelo's brain inside a giant biologically engineered robot, during the fight Dr. Wheelo's body got out of control and he accidentally steps on Dr. Kochin causing him to fall down a shaft during the fall he is shocked by an electrical wire causing his skin to come off his robot body and he explodes shortly afterwards killing him.