In his novel "Brothers Karamazov" Dostoevsky creates a most interesting portrait of Evil. Actually evil takes two very different forms and I think this is what makes it so great.
The first form is Pavel Smerdyakov. An epileptic lackey and cook. His origin is another interesting aspect. He is the son of a crazed woman and either Fyodor Pavlovich Karamazov, a most licentious and dissolute man, or of some criminal escaped from prison. So Evil sprouts from madness and crime or debauchery. He is a coward but a perfect criminal. In my opinion he represents the New Age Evil.
In contrast with him is Ivan Karamazov's illusion. A gentleman dressed rather poorly but impeccable in style, who lost his fortune when slavery was abolished (It may represent the freedom of mind. The moment man was freed from superstition.) He is a cheater and a corrupter of minds. He is The Old Age Evil. Dostoevsky calls him the Devil. He says that his mission is to stop people from believing in himself or God. He is just an illusion created by Ivan's ill mind, but so are the articles about the legitimacy of crime Ivan writes. Ivan thinks that if there is no God there are no rules and therefor crime is permitted. Smerdyakov reads this articles and believes them.
So Smedyakov is the pure evil. He murders Fyodor Pavlovich Karamazov. He does not repent. Dmitri Karamazov is blamed for his father's death so another man's life is ruined. But Smerdyakov is a simple minded epileptic. He is a victim of fate, son of a mad woman and adopted by servants. He is influenced by doctrines beyond his comprehension, atheism and "Everything is permited". In the end he commits suicide...
Smerdyakov becomes the antihero the opposite of Aleksey Fyodorovich Karamazov...