Professor Achimov is the narrative's primary antagonist. He kidnaps the aristocratic Mimimi and secures a specialized collar around her neck; this collar can fatally choke her when activated by a button concealed within his golden tooth. Achimov uses this device to blackmail Dorapin, a thief with a moral code, into serving his schemes.

Achimov's ultimate objective is world domination. To achieve this, he commands Dorapin to steal the "Friendship Telecards" from the heroic robotic group, the Doraemons. Achimov intends to harness the cards' energy to power his machine, designed to control all robots globally. This machine, referenced as the "Achimov Machine," operates from a technologically advanced flying fortress hidden above Paris.

Achimov manipulates Dorapin into using a transmutation wand to turn most of the Doraemons into statues. He then floods his labyrinthine fortress to corner the remaining Doraemons, exploiting their individual weaknesses, such as Dora Med III's fear of water. Demonstrating deceitful and sadistic tendencies, Achimov later reveals his promise to free Mimimi was a lie, taunts Dorapin, and electrocutes him after Dorapin completes the task.

Achimov's downfall occurs when Dorapin, realizing the deception, uses a card previously obtained from Dora Med III to destroy Achimov's golden tooth. This disables the collar's control and frees Mimimi. Achimov attempts retaliation by ejecting the Doraemons and Dorapin into vacuum space and transforming his fortress into a giant robot. After the united efforts of Dorapin and the Doraemons destroy the robot, Achimov flees to Earth where he is captured by the police.