“…the corruption of the best things gives rise to the worst.” David Hume, Natural History of Religion
Corruption is a keystone topic of a rational society. In the middle ages, I’m sure people noticed corruption, but they were limited in what they could do about it. In the modern day you can get away with saying quite a bit about leaders and powerful people. In a medieval setting even with had proof that someone in a position of power was engaging in abusive practices or downright crazy, one would have to appeal to a higher authority to support any accusation to get anything done. GRR Martin illustrates this rather brilliantly in Game of Thrones. Ned is a naive rationalist, acting much like a modern day detective; he finds the truth he is seeking, but it only brings disaster because in his society power and position mean a great deal more than evidence and reason, especially with no force to back them up.
In more modern societies we can at least complain about, analyze, and attack corruption. It has become something of a pastime in democratic societies, with endless accusations of corruption and fascination with scandal being fundamental characteristics of our society. Our fascination with corruption comes with our ability to analyze, recognize, and act against it. We see it take root in our institutions and want to do something about it, often forming political movements or pressuring our representatives to pass laws. In the middle ages if you encountered corruption you would likely just have to suck it up, unless you were or or had the ear of someone with power. People generally dealt with crazy kings by staying out of their way and either waiting for them to die or another noble to murder them. The right to free association wasn’t exactly a thing back then.
Fantasy Authors have long been fascinated with the idea of corruption, here are a few examples:
1) JRR Tolkien/Middle Earth: The Ring is an obvious metaphor for power, a reference to the Ring of Gyges from Plato, and it corrupts the wearer and even those who look upon it at times. Most Fantasy readers are set, one way or another, in their view of Tolkien and his ring but when you actually sit down and consider what it does, the one ring is a rather sinister piece of jewelry. The relationship of Wormtongue and Theoden is another example of corruption in middle earth. Saruman clouds Theoden’s mind, and uses Wormtongue as his proxy to manipulate the confused king, thus allowing him to hamper the entire nation of Rohan even before he send forth his armies. In Tolkien corruption is the purposeful tool of evil men. (A deeper analysis is possible, but you need to be really familiar with your lore.)
2) JK Rowling/Harry Potter: The use of Corruption in Harry Potter is fascinating. The first glimpse of Lord Voldemort is as he controls someone else and the way certain people are seduced to the Death Eater’s cause is very interesting. Voldemort is presented as a combination of Dark Lord and fascist leader, both modern and fantastica; the end result of unchecked corruption. Dolores Umbridge (book 5) is an example of corruption in progress, a representative of an institution that should be helping, but instead actively makes the situation worse by forcing her ideology onto everyone. The whole use of the ministry of magic in the books is very good for this theme in general, and one of the reasons I really enjoyed Harry Potter. In Rowling corruption is complex, not always part of a sinister plan, although sinister people do make use of it.
3) Robert Jordan/Wheel of Time: Corruption is omnipresent in the Wheel of Time. The male half of the power is tainted and causes madness, to the point that male magic users are seen as anathema. There is a blight in the north that is home to corrupt monstrosities: the trollocs, creatures created for war by evil sciences. The scale of the wheel of time is fairly large and the conflict is often black and white, but the idea that the structure of the world and the cosmos, the largest system of all, is not beyond corruption is a very modern notion.
4) Warhammer 40k: The super-heroic space marines of the Warhammer universe are beset on all sides by terrible aliens, yet the worst threats to the Empire are from within. The traitor marines who have sold their souls to the Chaos Gods, the various mutants, cultists, and rebels that eat at the foundation of the Empire are evidence of one type of corruption. The corruption of the imperial bureaucracy is another constant theme in the lore, a massive uncaring machine with the power to casually consign whole worlds to death, and a dead god-emperor at its heart.
5) Howard/Conan: Conan is the incorruptible savage, immune to the decadence that comes with civilization. The idea that civilization itself is corrupt is a slightly older paradigm that has been rejected because cities are cool, but it is fair to say that if you see a civilized man in Conan, he is likely a bad guy or just useless.
One of the more interesting uses of monsters in Fantasy is as a metaphor for corruption. Jordan’s Trollocs are corrupt science, Monsanto making soldiers. Tolkien’s orcs are actually horribly twisted elves, victims of endless brutalization that turns them into brutes themselves. 40k’s Tyranids could serve as a metaphor for many things with their endless need to consume and absorb everything in their path. Fantasy monsters are ripe for this kind of metaphor since having them be a corrupted version of something else makes them a little more terrifying. Perhaps that’s why we love zombies and vampires.
In the end corruption is a theme that binds modern fantasy together; from a crumbling Wall in Westeros that should get more attention than it does, to a ring that promises power while whispering doom.