This post wasn't easy to write. First of all, both dramas are veritable villain fests and some of the baddies are complicated characters (well, in one of the two shows at least ... ). Second, and related, it's not very easy to compare them. Actually, it's nigh impossible... Why the heck did I ever start comparing the two shows anyway?? ---*sigh*---
Be aware, there's [*spoilers*] ahead!
Faith: 신의Faith's villains are pretty 'standard'. Their main and almost sole dramatic purpose is to put obstacles in the path of our heroes on their way to overall happiness. Basically, you could exchange them for any other standard villain character and the story would develop essentially along the same lines: They are important to bring conflict to the story but they are, in essence, unimportant (unlike, i.e., Lord Voldemort, Sir Hugo Drax or the tribal band of murderous children in Children of the Corn). That's the type of villain that easily gets annoying, especially in a drama that has 24 episodes and very little story to tell.
Not so Faith's main villain, Ki Cheol (aka the King of the derp face) (Yu Oh-Seong). His slightly comical performance has been quite amusing for at least half of the drama. This character may be 'bad' and ruthless in theory, but he also has a human and almost likable side. Though we do not know exactly what is wrong with him, we know that he fears his (impending?) own death more than anything else. His main aim is to go to 'heaven' (= the future) with Eun-soo because he believes he can escape his destiny that way. I also like his looks - particularly the fancy hairnet (or whatever it is). In his villainy, he has developed from the cliched political intrigue-specialist who is a dick towards any King who doesn't follow his lead to a desperate quasi-madman who would do anything to preserve his life. And that's also his downfall as a character. As soon as he became more desperate than evil, a new villain was needed for the obstacles. That's when he got upstaged by the new baddie in town: Prince Doek-heung. Since, Ko Cheol is only a shadow of his former entertaining self.
However, if you understand his acts to be acts of desperation, this character makes some kind of sense. He knows very well that he'll either become King - or die. His 'evil' deeds are ensuring his survival - nothing more and nothing less (okay, maybe he also just evil on the side, i.e. the sneer when burning her precious notebook). I find it hard to blame him for that - desperate times call for desperate measures. Unfortunately, he isn't showing any other emotions other than this survival instinct (and fear and narcissism), which makes it impossible to have much empathy. I simply don't care what happens to him - which is a shame, given his promising entrance as Faith's new top villain (and by the way, the cheap and oh-so-visible fake hairpiece coming up from his ears makes me angry every single it appears on screen with him).
However, the biggest writers' blunder in the villain department are the two characters of Cheon Eum-ja (Sung Hoon) and Hwa Soo-in, pledged brother and sister to each other and Ki Cheol. What a wasted opportunity they are! While I never liked her - she is an over-the-top and cliché character in looks and in acting - there were bits and pieces in the earlier episodes that made me hope Eum would become a more interesting character. His imperfect superpowers or his, as was hinted, crush on his 'sister' Hwa Soo-in could have been developed further to make him more than just a manga-like character with gray hair and a flute. Alas, the evil 'siblings' have become nothing else than a listening-device and a bully for Ki Cheol, with about 3 minutes of screen time in every episode. In other words, they have become utterly redundant. At least give them a meaningful and glorious death, writers!
Arang and the Magistrate: 아랑사또전In Arang, the villains serve an entirely different purpose than in Faith. They are not about hindrances, but they are at the heart of the story. That's the trademark of Arang - not to waste a single character (apart from the Bangs) and give each and every one of them a purpose, a storyline, and development. In the case of some of our villains, the writers even make us wonder whether they really deserve to be on a list of villains.
That's certainly not true for Lord Choi (Kim Yong-Geon). Lord Choi is actually the most purely evil character on this show (and would also be in the other, were he in Faith). And how well this actor was cast ... the heartless sneer, the condescending laugh, the ruthless eyes; just perfect! It is Lord Choi that has brought misery into the Magistrate's life, by destroying the honor and family of his mother, who cares for nothing else than revenge - to the point where she abandons her son to die. And it is Lord Choi that continues to bring misery to everybody around him, and particularly to the poor people in his town. As the show progresses, more and more of his evilness is unveiled. And it's a very selfish evil, without any regret and without any regard for life other than his own. He is, as Jade Emperor and Hades put it, a monster in human form. I am currently not sure the show will deliver a Happy Ending in this week's finale ... but I do hope that Lord Choi gets to suffer a lot for his crimes! (If not, I'll call Vampire Prosecutor Min Tae-yeon to bring justice to you)
As the story progresses, however, we learn that there is something/somebody inhabiting Eun-oh's mother, and that 'thing' has unsettled the balance of the universe. And it is not a coincidence that the thing is now inhabiting Eun-oh's (awful) mother, because poor Eun-oh's purpose is to be a weapon in the hands of the Gods to help restore the balance (by putting the creature back where it belongs: hell; and only a relative can do it). We then learn that this 'thing' is in fact an ex-Fairy of heaven, and the sister of the chief Grim Reaper at that: Mu-yeon. At first, she seems selfish and purely evil, living in the body of willing humans, eating pure souls (and thereby killing innocent girls) to keep herself strong. But we are also shown her desperation.
Mu-yeon is also a very tragic figure, crippled by eternal love that can never be - a series of lifetimes shared with the same man (Mu-young, now the Grim Reaper), sometimes as lovers, but also as siblings ... but never happy. In her desperation, when seeing him again in heaven, she asked him to come back down to earth with her, to live as two people that can finally have love. But, noooooo!, he turned her down (does that also make him a villain? Should I add him here?). That creature now gets ready to lead an eternal life on earth - forever lonely. It's actually quite heartbreaking. If anything about this shows ending seems clear than it's that she has it coming.
And then, there is Joo-wal (Yeon Woo-Jin) - the multiple murderer that never wanted to be but still is. He is even more tragic than Mu-yeon, who at least had a choice between good and evil. Joo-wal is Mu-yeon's minion and brings her souls. He also kills Arang once and almost twice ... but he also experiences love for the first time with Arang. We have recently learned that he couldn't take the killings, and that he had Mu-yeon erase his memories, but that surely doesn't absolve him.
He is a dark but sad figure and I have been struck by the similarities between him and Eun-oh several times. In a way, they are half-brothers. It might not be real mom that Joo-wal has been living with, but evil-fairy-mom is only slightly different from the mom that Eun-oh experienced. So, what drives them is similar: they both crave love from the same twisted person. Joo-wal is what Eun-oh could have been, if not for people like his father (who has always protected him) and his wonderful servant Dol-Swe. Also, Joo-wal is a weapon (Big Bad’s weapon for collecting souls and vessels) and Eun-oh is a weapon (Jade’s weapon for neutralizing Big Bad). Both have been saved from death (Eun-oh literally, Joo-wal from the death of starvation), but both men are now playthings in the hand of supernatural creatures. That said, Joo-wal is by far the more tragic figure. He is doomed to me – his sins are too great, he cannot ever be happy. With his feelings awakened and his memories coming back, the real suffering has started. The guilt will crush him. I could imagine that the only way he can somehow atone for some of his sins is to sacrifice himself in the end - hopefully for the good of either Eun-oh or Arang, or both.