Eva Kant is the girlfriend of Diabolik, a criminal that operates in a fictional town called Clerville. Her first appearance is in the 3rd episode, in 1963: she is an aristocratic woman and Diabolik wants to rob her diamonds but they fall in love. Shortly after Diabolik is arrested but Eva saves him from the guillotine. From that moment she becomes a criminal and sidekick of Diabolik: their only goal is to steal money, jewels and gold and they almost always achieve it
In the the first 20 episodes Eva is a little scared by the cruelty of Diabolik but little by little she becomes ruthless almost like him and they do not hesitate to kill to steal. From the 200th episode, both of them become less cruel and prefer to drug their victims rather that kill them.
She is blonde and attractive and very refined. She uses plastic masks while going somewhere out in public to avoid being recognized and to impersonate her victims.
Diabolik plans most of the heists and he commits most murders. Even though, with the aim of making thefts, Eva is responsible for of lots of homicides and crimes. In her first appearance, in the 3rd episode, she and Diabolik fall in love but immediately after, he is arrested. To save him from the guillotine, she organizes a stratagem: she drugs her boyfriend George Caron, puts a mask of Diaboliks' face on him and introduces him to the cell of the robber. The following morning George is killed while Eva and Diabolik escape and begin their criminal life toghether.After that, her following premeditated murder appears in 72th episode: Eva and Diabolik are tailing a woman that transports drugs with the aim to discover who is the boss of the traffic. When they note the police are also tailing her, they chase the woman fastly with their powerful Jaguar E-Type. Once their Jaguar passes the car of the woman, Eva pushes a botton: a little rocket is fired and hits the car behind them, killing the woman immediately. Before that, Eva had helped Diabolik to kill some people. In the 70th episode Furia Criminale, Diabolik wants to impersonate Alfredo Wirton, a nephew of a rich countess and finally steal all her jewels. To do that, Eva pretends to have the car engine damaged and asks Alfredo to help her. Alfredo, impressed by the woman's beauty, stops and goes out of his car. While he is checking the engine, Diabolik assaults and strangles him. After that, the two criminals return home to prepare the mask of Alfredo.
In the following episode, I due nemici, Diabolik and Eva are fleeing from police after a jewelry heist. They need to take a car so, at a certain point, he orders her to lie down on the ground. Eva obeys and a car stops. A man goes out from his car, very worried about her health conditions. When the man is close to Eva, Diabolik suddenly strangles him. After that Eva stands up and both of them go home with the stolen car and the jewels.