Literally every character can be interpreted as the "good" or "bad" guy at some point. What's interesting is that three of the main characters in Vengeance—Spartacus, Crixus, and Agron—all have different opinions on almost everything that happens, despite being on the same side, which makes for very different interpretations of their characters. Is Spartacus a brave and compassionate man, or a single-minded idealist? Is Crixus's devotion to Naevia admirable or selfish? Is Agron a pragmatic leader or a selfish brat?
Come War of the Damned, Crassus is open to considerable interpretation. Is he a loyal servant of Rome who fights out of a sense of patriotism, or a power-hungry politician who fights for greed and personal advancement? Is he a a Benevolent Boss who genuinely cares about his slaves, or a Control Freak who desires to own people as property, even though he could afford to free them and then employ them if he chose to? Are the disciplinary actions he inflicts on his troops barbaric and overly harsh, or a necessity given their repeated failures against Spartacus? Was his crucifixion of Kore really necessary? Even if he couldn't spare her life, surely he could have given her a more merciful end?
Cossutius, from the Vengeance episodes "Empty Hands" and "Libertus", and the prequel season Gods of the Arena, is the worst example of unchecked Roman excess. A Smug Snakearistocrat, he extorts a favor from the House of Batiatus by requesting a “show” from a virgin slave girl. He selects the girl Diona as he knows he can hurt her more and forces her to lose her virginity to a brutish, dirty, filthy gladiator, mocking Diona all the while as an “example“ of how ugliness and beauty co-exist before anally raping her during her ordeal. Cossutius later shows sheer glee at Diona's execution, and at a Roman party is the first to gleefully torture a bound Gladiator for nothing more than entertainment. Furthermore, Cossutius is a serial rapist. He makes it explicitly clear he chooses Diona due to her being a virgin, and makes it quite clear virgins don't exist in his household for that reason. In sexual sadism, Cossutius is well above his fellow Romans.
Evil Is Cool: Batiatus, Lucretia, Glaber, Illithiya, Ashur, Theokoles, Caburus and Caesar breathes this trope.
Evil Is Sexy: Where do we start? For the girls, there's Ilithyia, Lucretia and Seppia.
Evil Versus Evil: Aside from the Roman elite constantly screwing each other over, the rebels eventually fall into this as well. Crixus, heavily goaded by Naevia, develops such an unrelenting hatred of Romans that he wants them all dead. Not just the wealthy slaveowners, but even the common people. When he finally breaks with Spartacus in War of the Damned, it is because he will accept nothing less than total slaughter and the destruction of Rome itself. Not that this would end slavery as an institution, as other nations also practiced it. Plus the rebels already had more than a little bit of a Might Makes Right social hierarchy forming amongst themselves. So the final battle between Crixus and his forces against Crassus and his legions takes on this tone.
Fans Prefer the New Her: Acknowledged in-universe. Lucretia looks quite good when she goes back to wearing her red wigs in Vengeance. Unfortunately she's wearing them at Ashur's orders - after he's been raping her. Notably there's one scene where Illythia complements Lucretia on how good the red hair looks, only for the latter to shudder.
"Funny Aneurysm" Moment: The Season 1 DVD special features showed Andy Whitfield, exhausted after a workout, saying he hopes he's still around when the series ends. He stepped out due to cancer and died in 2011.
Genius Bonus: The very first episode has a subtle quote of Chief Joseph's famous line, "I will fight no more forever." Spartacus's wife asks him a hypothetical, "You will fight no more?" His response begins, "Forever."
Growing the Beard: The first couple episodes of Blood and Sand are generally agreed to be not very good. The show starts hitting its stride around episodes three and four, for various reasons; the actors are obviously getting used to the sentence structure of their lines, the show isn't trying so hard to be 300 (the influence is still obviously there, it just isn't as blatant), Hannah started really hamming it up as Batiatus, and characters in general became more fleshed out.
Guilty Pleasure: The show is very violent and sexual, but it is also very enjoyable, so many watch it with a little bit of guilt.
Harsher in Hindsight: Episode 11 of Blood and Sand involves Spartacus being bedridden due to a severe infection, and the medicus doing everything he can to save him. There's even a scene in that episode where Spartacus sees his dead body on a morgue. Andy Whitfield, the actor who played Spartacus, had to leave the role due to cancer. Tragically, he lost the battle a year later.
When you consider the great length at which Lucretia extols her hatred of Thracians and then you remember Xena was Thracian, it is hard not to chuckle.
Before Agron was revealed to be gay, the show caught a lot of flack for apparently playing up the Bury Your Gays trope. Agron and Nasir are the only two of the main protagonists to survive the war.
After this show wrapped, large chunks of the cast moved en masse to Arrow, two of which are Manu Bennett (Crixus) and Cynthia Addai-Robinson (Naevia.) Considering they play Deathstroke and Amanda Waller on that show, going back and watching them as a couple on this show looks like a match made in hell.
After this show wrapped, two alumnae will went on to play DC Comics villain Captain Boomerang in two different adaptations; Nick E. Tarbay (Ashur) in Arrow and Jai Courtney (Varro) in Suicide Squad.
Liam McIntyre will appear in The Flash (2014) as the (second) Weather Wizard, which is kinda appropriate for an actor who played a character whose Red Baron is "The Bringer of Rain". Additionally, Liam's character will be replacing said character's brother after he died, much like how Liam himself becomes the new Spartacus after Andy Whitfield's death.
If you're aware of the New Zealand sitcom Diplomatic Immunity, both Craig Parker (Glaber) and Lesley Ann Brandt (the first Naevia) starred together in that as love interests. Hilariously in that case it was Brandt's character who outranked Parker's (she was the king's niece).
Holy Shit Quotient: Very high, as the episodes are specifically written to contain their emotional impact into specific key scenes.
Vengeance Episode 7 had a fight between Spartacus and 7-foot tall guy Sedullus. Spartacus sliced his face off with one strike and HIS BRAIN FELL OUT!!
Ho Yay: Almost pointless on a show where Hide Your Gays is a strongly averted trope. But it still happens.
Hints of this between Glaber and Marcus in Vengeance. Especially given Marcus' obvious devotion and Glaber's tendency to heed his advice over anybody else. It is notable that Marcus is pretty much the only fatality that Glaber shows actual sorrow over (or even more than casual interest in).
War of the Damned introduces Tiberius and Sabinus, who may be more than best friends. Although Christian Antidormi has said they were not a couple, he and Aaron Jakubenko really missed their marks in their performances if that was meant to be the case. note What Antidormi said is that their relationship was supposed to appear ambiguous in early scenes, but it resolved itself as just friendship as the arc went on. Also, the fact that Tiberius seeks revenge for Sabinus' death by raping his father's lover adds the subtext that taking his father's lover was somehow recompense for the loss of his own. He also demonstrates when he rapes Caesar that he is not averse to sexual contact with men.
It was around even as early as Blood and Sand, especially between Spartacus and Varro.
Spartacus: [After a sparring match] Your head is mine. Now, how shall I mount it? [Big goofy grins from both of them]
For a SMALL moment you feel bad for Glaber once he is made aware of the conspiracy to not only have his marriage dissolved but his child aborted by his wife, father-in-law, and rival.
Likewise, Ilithyia. Despite being a royal cunt, it's hard to not feel sorry for her after Glaber fucks her life up. It's mainly due to Viva Bianca's acting though.
Lucretia. Oh, Lucretia. It's easy to forget how she sent Naevia to a fate worse than death after everything that's happened to her since then.
Tiberius. As incredibly vicious as he is, it is very clear that his father's often cruel attempts to harden him are what turns him evil. In particular being forced to kill his Heterosexual Life-Partner (or possible lover) in the decimation it is easy to see why he went sailing right across the Moral Event Horizon.
Les Yay: Between Ilithyia and Lucretia, with some Foe Yay thrown in as well.
Saxa has bisexual tendencies and seems to pursue an offscreen relationship with one of the rebel slaves named Belesa, as they have at least three intimate moments together in War of the Damned.
Also Between Naevia and Diona in Gods of the Arena; They're close friends, who've both stayed virgins (not so easy in the House of Batiatus) especially since they're seen early on thinking dirty about the gladiators. After Diona is raped by a Roman, Naevia worries to Diona that they aren't as close as they used to be. And in episode 5 as Naevia helps Diona escape, they share a kiss on the lips goodbye, and a promise to see each other again one day.
Crixus takes this all the way to the point of Wangst over Naevia. Unlike Spartacus, who mostly mourns privately and generally only mentions his late wife to people he is close to, Crixus indulges in dramatic public displays of woe.
Gannicus feels deep guilt over Melitta, and his betrayal of Oenomaus, as well as various other things. He usually covers by drinking.
Moral Event Horizon: Tullius (from Gods of the Arena) at first is just as vile as the other Roman nobles. He crosses this with the murder of Gaia who was somewhat likable. Even worse, he did it just to show that he could do it and get away with it. He now is a complete psychopath with no redeeming qualities.
Ilithyia crosses it when she manipulates Numerius into forcing Spartacus to kill Varro. She'd done some bad things before that, but even killing Licinia in a blind rage doesn't quite compare to forcing Spartacus to kill his best friend because she just hates him that much.
If he hadn't crossed it already, Glaber definitely crosses it when he crucifies an innocent slave, just to show his power over Ilithyia.
Naevia, of all people, showed signs of crossing this since War Of the Damned started. She crosses it fully in Decimation when she batters Gannicus with a giant rock after he tried to get Crixus to snap out of his madness. Then she gleefully participates in the slaughter of every Roman citizen within the city.
Batiatus having Sura killed on the way to the ludus so she can die in Spartacus' arms.
Ashur manipulating Dagan into being sodomized by a Roman elite in Gods of the Arena could be considered this for him.
Tiberius raping Kore, who had always behaved more warmly towards him than even his own mother, as a way of getting revenge on his father for Sabinus' death in the decimation.
Narm: For viewers in the Australia/New Zealand region, the barely-disguised Kiwi accents can be this.
Seriously, look at John Hannah's face during the credits for Season 1.
In Vengeance Glaber has a party, during which the upper class of Capua and Rome take one of the captured Gauls and proceed to string him up and take turns cutting bits of flesh off of him...always careful to do so in such a way that he won't bleed out or die.
Replacement Scrappy: Cynthia Addai Robinson replacing Lesley Ann Brandt as Naevia. Unfortunately for her, the cast change also coincided with a massive personality change for Naevia. The character had gone through a Trauma Conga Line and at first was a Damsel Scrappy but then became a Blood Knight. General consensus seems to be that Lesley Ann Brandt would have been able to make Naevia seem sympathetic despite this - but that the change in actress made it seem like it was a completely new character.
Spartacus charging Crassus and his Mooks all by himself.
The shield graveyard.
So Coolits Awesome: With its sky-high kill count, expert fight choreography and its creatively brutal scenes of violence it certainly gets this reaction from even the most casual viewers.
Stop Helping Me!: It was accidental, but Ilithyia convincing her husband to make a grab for glory in the pilot episode really screws him over. Convincing him to attack the rebels before they are sufficiently weakened in Vengeance episode 10 would have had the same effect if Spartacus hadn't pulled his Fast-Roping trick first.
They Wasted a Perfectly Good Character: Diona in Gods of the Arena is mainly a side character who gets minimal screen time. She's killed off in the finale to wrap things up, when she could have played a bigger part in Vengeance especially as a character besides Crixus who has a connection to Naevia.