The story is about a hard-drinking, well-to-do, and evil father who makes fun of everything noble. He engages in inappropriate actions at every opportunity. And when his children were infants, he neglected them unintentionally, but because he forgot them, and forgot their existence because of his preoccupation in his decadent life. His eldest son, Dimitri, was a passionate man capable of sincere love for two women at the same time, and you will learn about them in the novel and the story behind them. This son often argues with his father over money, and competes with him over a woman they both fell in love with.
As for the youngest son, his name is Elisha, and he is one of Dostoevsky's attempts to create a pure and innocent Christian personality. Alyosha, the wise and handsome monk, tries to put Christian love into practice. The narrator announces him as the real hero of the work, but everyone is usually more interested in the character of the educated middle brother Ivan, and in my opinion he is also the real hero of the work and the most important character in the novel.
Like Raskolnikov from Crime and Punishment.
Ivan Karamazov is very intellectual, non-religious, considers himself an atheist, and argues that if there is no God and no immortality then everything is permissible. Even if not everyone allows it, one is only responsible for one's actions, not for one's desires.
In the novel, it can be noted how the monk Elisha tries to get close to his atheist brother Ivan, and tries to engage him in spiritual, religious, and philosophical discussions in order to know what is going on inside his brother's mind and way of thinking.