Lots of suggestions so I think I'll just rapid-fire these with more shortform explanations for their rankings:
Randal Graves (Clerks) - Smokes pot, is a decent worker, and is a good friend to Dante, giving him advice when he can. I'd say he's also in Limbo (Flawed Neutral).
Omni-Man (Invincible) - Slaughtered hundreds of people for dogma and for the glory of his empire. He loves his son and probably can be redeemed, but those murders by and large overshadow anything he's done. Fifth Circle of Hell (Sociopathic).
Malcolm Merlyn (Arrow) - He causes destruction for selfish reasons, has had many people killed over the series, if not personally murdered them, and is primarily responsible for everything that happens in the series. Hard not to say he doesn't belong in The Seventh Circle of Hell (Irreparably Selfish)
Butters (South Park) - Well, I'd have to think on it, but Butters is generally good-natured, he's a kid after all, and is usually pretty friendly. I think for the purposes of this thread, we'll go with the Stick of Truth to pinpoint where he'd belong in the list. He's a healer and essentially a paladin, he can also make himself the target of others' attacks to protect others, and he's among the nicest characters to The New Kid. He belongs in Purgatorio (Flawed But Good).
Anakin Skywalker (Star Wars) - Ah man. This one is also a tough one, specifically because he does attempt to redeem himself in the end and succeeds in bringing back balance to the Force. Yet his list of crimes and flaws are vast and deep. He's selfish, arrogant, independent-minded, balks at authority, and suffers from lust for his wife Padme despite his oaths, making him an oath breaker. Then he is a willing part of Order 66, and massacred an entire group of children who were looking to him for protection. Say what you will, but Anakin Skywalker, and by extension Darth Vader belong in the Sixth Circle of Hell (Malicious).
Light Yagami (Death Note) - He at first uses the book to kill criminals who have slipped through the cracks of justice, or are the dregs of society, but he goes completely mad with power, and falls victim to his greatest flaw, his narcissism. Even before he finds the death note, we are introduced to Light as him being an obsessive perfectionist who views himself as smarter than everyone around him. The Death Note merely allows his ego to grow as he fashions himself the god of a new age. He murders and tricks people around him, and continues a long series of vicious crimes that eventually end in his own death. Light definitely belongs in The Eighth Circle of Hell (Irreparably Sociopathic).
L Lawliet (Death Note) - Pretty quickly, this is a character who's flaw, like Light, is his narcissism. Though this version manifests largely in his criminal deductive skills and law enforcement; he considers himself the greatest detective in the world. Yet in the series itself, he's shown to flaunt rules and throw other people under the bus to do what he has to do to solve the crime. One of the first examples is his lamb-to-slaughter sacrifice of Lind L. Taylor. L probably belongs in The Second Circle of Hell (Mildly Sociopathic).