Behemoth from rpg.net said this, about brands of evil (not in a quote box because the italics make it painful to read):
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What I really like about the Order of the Stick is that each of the main villains are a totally different kind of evil.
Take Xykon. He’s the Post-Sauron Dark Lord done right. Now, obviously, you can’t have him off-screen occasionally casting his baleful eye on the protagonists, and to be fair, that hasn’t really been the thing since LOTR, because people want a villain who, you know, might say something memorable. (Not to say I don’t like Sauron, he is awesome, but I don’t think he should be the model of the Fantasy Dark Lord).
Xykon is Evil purely for the sake of Evil. He is comically Evil. He is cartoonishly Evil. He is Evil with a capital-E always and forever. And while you can laugh at him, and think that he is less intelligent than Red Cloak, he is still evil. He kills real people. The sequence with O-Chul doesn’t just make O-Chul seem bad-ass because of what he survives, it makes the terrible things Xykon has been joking about real. All those people that Xykon killed out of hand were like O-Chul, except weaker and slower and ultimately less lucky.
And Xykon can come up with schemes too. Look at how he breaks Red Cloak. Xykon is evil as the monolythic Evil of fairytales and fantasy books, and he is in no way compromised by this.
Nale is a bastard. Selfish, self-involved, malevolent, and vengeful, Nale is a modern evil, he’s the terrorist leader or the master criminal or the genius sociopath. He comes up with elaborate plans, he is inherently a schemer, and he likes to take what he wants and do what he wants and he doesn’t care what happens. He is Lawful Evil only in the fact that he takes a perverse pleasure in following the letter of his word, or in twisting laws into following his own ends. Look at his plans to take out Elan- they involved ultimately using a police force to do his dirty work for him.
Nale is also not really that intelligent. He’s probably smarter than Xykon, but he doesn’t have the ability to steam-role over whatever is in his way. He also relies way too much on his minions, again fitting into the master criminal archetype. He surpasses the archetype like Xykon, but only in his pettiness. Xykon takes fairytale evil and makes it real through the impact of his acts. Nale takes ‘genius sociopathy’ and makes it real through his own faliability and entitlement. He is at heart a selfish wanker, and he never manages to become as baroquely terrible as Xykon.
Tarquin is a stylish villain. He is The Stylish Villian, the villian with class, charm, style, wit and an ability to make the audience sympathise with him. He is also genre-aware, which he shares with Xykon to an extent, and acts in a way that makes it hard for the audience to truly hate him. He also makes his villiany ‘real’, and in a similar way to Xykon. When he has a group of escaped slaves crucified and set on fire, we have already witnessed these slaves being freed, in effect we thought that they had got away. His massacre is executed with aplomb, but it makes us think about what a Stylish Villian really is.
Tarquin shows up the archetype of the stylish villian by demonstrating that, just because you might have good dress sense and a witty personal manner, doesn’t mean that you aren’t committing war crimes or acting in a base fashion. Take his destruction of the Free City of Doom. He does it to further his plan to dominate the continent, but he also doesn’t miss the excuse to kill the husband of the emissary.
A lot of people have been saying that he is essentially different than Nale, but to be honest this is only because he has a sense of style. Take that away, and you have a mass murdering military leader who uses a war to kill the husband of the woman he wants to force into marrying him. Sometimes, Style doesn’t matter.
Lastly Red-Cloak. Red-Cloak has one of the most interesting arcs of all the villians, probably the longest and most in-depth. What has suprised me is that a lot of people have written on previous threads that they expect Red-Cloak to go over to the side of the Order during the End Game. This is because Red-Cloak is doing evil not as a means to itself, like Xykon, or out of selfishness like Nale and Tarquin, but because Red-Cloak has a cause. He even has a good cause, the Goblins are oppressed and beaten down and the world is unfair towards them. But I hoenstly think that Red-Cloak is the worst of all the villians.
Does Red-Cloak really want the Goblins to be freed by any means necessary? No. If he did want that, he wouldn’t have signed on with Xykon instead of working with Right-Eye in a town where Goblins and people were living side by side. Red-Cloak is more interested in being Right and in personally freeing the Goblins than creating equality. He rationalises to himself that he is doing the right thing, and that he is working for the good of goblin kind, and he takes expeption to himself when he realises that he is a racist against Hobgoblins. He also enslaves a city full of innocent people, never mind the fact that the Paladins of Azure City were engaged in genocide against the Goblins, the simple fact is that two wrongs don’t make a right. You don’t get to claim the moral high ground when you are performing experiments on captured slave labourers, no matter what their rulers may have done to you in the past.
Red-Cloak’s evil is the worst because his is the evil that has done the worst things in reality. Xykon doesn’t exist, and can’t exist. Nale and Tarquin are plays on archetypes in fiction, though they both have roots in reality. Red-Cloak is a leader of a beaten people trying to give them back their self-respect through warfare and conquest and enslavement. His evil is made worse by the fact that he has a justification, by the fact that he is smarter and more sympathetic than Xykon. In order to be right, to gain the moral high ground, he murdered his own brother who was attempting to create exactly what he said he wanted- but without violence. Red-Cloak has to be right, that’s why he has done everything he has done. I honestly can’t see him ever changing sides because of this.