Complete Monster: Arkady Svidrigailov. This guy began with raping and killing a 13-year old girl and didn't get any better. For the Evulz he had Driven to Suicide a faithful servant, killed his caring wife, molested and possibly tried to rape Dunya, and God knows what other atrocities he committed. A crazy, sociopathic nutjob who truly beleives that Evil Feels Good, Svidrigailov could be easily considered the most inhumane and repulsive character of the novel.
Moral Event Horizon: The whole book is an examination of Raskolnikov's belief that someone can justifiably cross the line for the greater good. And he crosses it when he murders not only the old woman but also her sister for catching him at the scene of the crime. He spends the rest of the story suffering from his inability to accept what he did.
He also ponders his similarities with two other characters who made the same choices and managed to live with what they did. Luzhin framed Sonja for theft for his own purposes and as for Svidrigailov the Complete Monster entry summarises all his acts in life.
Seinfeld Is Unfunny: Rodya is a college dropout with mental issues, who thinks saving his sister from sexual abuse gives him an excuse to kill someone. Yes, I just described 50% of all Cold Case episodes.
Tearjerker: Raskolnikov's dream about a poor old mare getting beaten to death. Which is also mad Squicky.
The Woobie: The prostitute Sonya, who was forced into it by her family. Raskolnikov and (arguably) Semyon Zakharovich Marmeladov are of the jerkass variety.