The idea of ranking the worst traits and actions of the Deadwood characters seems like an ineffectual one. After all, the characters on Deadwood tend to be so detestable and so horrifically evil (in many cases) that it's harder to narrow down the horrible deeds and qualities than it is to think of them.
Even the tenth character on this list would still be one of the top-ranking antagonists of most other series. That was just the way of Deadwood. Not much good passed through that town so they had to take hope and kindness whenever they could get it.
E.B. - Full-On Greedy
As the mayor of Deadwood, E.B., portrayed by William Sanderson, is completely corrupt. He never operates within the town's best interests. Instead, he's driven solely by his major sense of greed.
E.B. always wants more and he puts many people at risk because of it. Fortunately, nothing too negative stems to others from his actions. He's the one who faces his own consequences.
Merrick - Journalism Conspirator
Speaking of corruption, A.W. Merrick fits that mold perfectly. While E.B.'s corruption and greed comes in legislative and leadership forms, Merrick's stems from his position of power in the Black Hills Pioneer.
Very rarely does honest journalism and reporting flow through Merrick, though. He's a puppet for Al Swearengen's propaganda machine. In Deadwood, unless one is looking out for their own skin, Al is not an ideal figure to be aligned with.
Ellsworth - Engaged In Cover-Ups
Ellsworth is one of the more genial figures about Deadwood and he has garnered a lot of respect from the people he interacts with. However, he's also quite submissive when it comes to the fear he has of enforcers.
The worst thing about Ellsworth is that he said nothing when he witnessed the murder of Brom. His motivation for doing so is understandable, considering the immense danger he was in. However, it's still far from a reputable act.
Alma - Troubled With Addiction
The worst thing about Alma is something entirely out of her control: she struggles mightily with addiction. Alma often leads herself down dark paths because of her addictive nature and it's a shame that she never received as much help as she should have.
Ultimately, Alma manages to shake her issues, but the impact her addiction has on Deadwood residents is nothing compared to how it impacts her. In this case, worst means, worst for her.
Seth - He's Hot-Headed
Seth is maybe the closest thing Deadwood had to an upstanding paragon of morality. Even then, he still had his own dalliances with strong flaws.
Anyone who is able to forge a bond with Al over the course of years is not someone who can be wholly innocent after all. Seth has an extremely short temper and it often results in him painting himself as a foe to many of Deadwood's more nefarious residents. Fortunately, his proclivity for anger was used for mostly just purposes.
Doc - He's A Grave Robber
Like Seth, Doc's tendencies lean towards being a good man and a respect figure in Deadwood. After all, a medic in a western town with as much bloodshed as Deadwood is a valuable commodity.
However, Doc has skeletons in his closet. And he has skeletons on the mind, too. Frequently in his past, Doc once disclosed, he robbed graves. (And yes, that's plural.) It's a form of desecration that doesn't harm the living, but it's not providing rainbows to the dead either.
Cy - Torture As Force
For the most part, Cy Tolliver comes across as an upstanding citizen. Of course, this is nothing but a front for his nefarious behavior, which manifests in what he directly causes and what he pretends not to notice.
The worst part about Cy, though, is that he turns to torture quickly. His violence is never quite on the level of some of the town's more ruthless killers. But the fact that Cy inflicts pain upon others warrants inclusion on the list.
Dan - He's Incredibly Violent
In terms of characters who aligned with Al, Dan is definitely the consigliere of Al's horrible behavior (more on that later). However, Dan does not rank as highly because his immense penchant for violence is never done coldly.
Dan feels acutely aware of his own livelihood and how killing is not an act that should be done on a whim. It's a grave matter. Dan is not a good man, considering how frequently his violence leads to death. But others are still worse.
George - Heartless Killing
Dan is a heartful killer at the end of the day, but George Hearst ranks above him because of his personality, which is defined by heartless murders. When his workers discuss unionization, George dispatches them without a second thought.
Considering how evil George was as a miner in Deadwood, it's probably for the best that he only became a main character by the end. Viewers would have struggled to stomach his actions and Al's actions throughout all three seasons.
Al - He's Not Just A Murderer
There is no way that Al Swearengen would not be ranked first on a list of the worst things about Deadwood characters. Others may be murderers, but Al is the worst of all things rolled into one.
He doesn't just kill, he also tortures. He isn't just sexist, he's also racist. Al Swearengen is an absolutely horrible person who only made the world worse by being on it throughout Deadwood. The fact that he's not just a murderer has to be the worst thing about him, bar none.