A good villain makes any story that much richer and exciting. Great video game villains inspire you to fight against overwhelming odds, spur you on through puzzles, waves of enemies, and cutscenes...all to ensure their ultimate destruction.

Some video game villains have reached the status of cultural icons—Bowser, Ganondorf, and Doctor Eggman, for example—but there are plenty of others worth mentioning, or love-hating. In no particular order, here are five of the most compelling, dynamic, and fascinating modern video game villains for your consideration. Warning: this list contains SPOILERS for the Mass Effect, Portal, BioShock, Mother, and Warcraft series.

The Reapers – the Mass Effect Series

Mass Effect's Reapers are kind of like the universe's malevolent scientists. They allow organic life to develop and create synthetics, then swoop in from dark space to harvest advanced life forms, processing them into new, Reaper-fied. Drawing heavily on Lovecraft's Cthulhu mythos, the Reapers are vastly intelligent, terrifying, and nigh invincible—they can be destroyed, but it takes a united galaxy and an incredible amount of firepower to destroy a small number.

Worse, they're the puppetmasters behind the entire galaxy. Mass relays? Their invention. The Citadel? Theirs. Keepers? Theirs. Every achievement and symbol of peace is a part of the Reaper's master plan for the galaxy. Though they were the creation of an ancient race, their advancement has superseded that of their creators, and they now rule the galaxy from afar—until, of course, Commander Shepard comes along.

GLaDOS – The Portal Series

As one of the most-quoted video game villains of all time, GLaDOS deserves a spot on any top villains list. She's cold, calculating, and snide, but what makes her compelling isn't just her cruel sense of humor, but rather the way her character develops over the course of the series.

At the beginning of Portal, GLaDOS is merely the voice administering Chell's tests. Her voice is flat and robotic, and while her delicious snark is still present, it's not until the player starts venturing outside the testing chambers that you get a taste of her true personality. She's manipulative and clever, trying various approaches to bend Chell to her will. In the ultimate battle, you're able to dismantle her piece by piece, revealing how much effort has been made to control the rogue aspects of her personality.

Portal 2 takes GLaDOS's personality to new levels. It's revealed that Aperture Science's CEO had the essence his assistant, Caroline, extracted to serve as the core for GLaDOS. Worse, there are implications that Caroline may be Chell's mother, making all those 'orphan' jokes feel a lot harsher.

Andrew Ryan – BioShock

Andrew Ryan is idealism gone horribly wrong. While there are a lot of criticisms of meritocracy and free-market capitalism already, personifying those ideals in Andrew Ryan makes it painfully clear how a society run by a man with complete disdain for altruism rapidly turns to chaos.

Ryan isn't the only antagonist in BioShock, and there's a strong case to be made that Fontaine's corruption of Ryan's lofty ideals makes him the more evil one. But Ryan's refusal, even at the moment of his death, to let anyone else have control over his life shows that he places his ideals above all else. He's the perfect example of how an ideology, even one as supposedly benevolent as free will, can be destructive.

Giygas – The Mother Series

The final boss battle of 1994's EarthBound likely shattered the fragile minds of more than one young child. Like Mass Effect's Reapers, Giygas is directly inspired by Lovecraftian horror, particularly his incomprehensible form and his power to corrupt objects and animals.

Inspired by designer Shigesato Itoi's early exposure to an adult film, Giygas embodies a conflation of love and torment as a result of the loss of his adoptive human mother. Giygas is defeated by music that reminds him of his lost mother in Mother, and by the power of prayer and human emotion in EarthBound. But that doesn't erase the creepiness of the shifting background, distorted music, and the horrifying moment when Giygas appears to turn off the player's TV.

Arthas – The Warcraft Series

Arthas is the embodiment of the idea that "the bigger they are, the harder they fall." Once the generally good, if headstrong, Prince of Lordaeron, the paladin Arthas falls to the power of Frostmourne, a runic sword that destroys his soul and turns him into the Lich King.

What makes Arthas an interesting video game villain is his desire to do the right thing—though he's shown to be vindictive, his good intentions are ultimately his undoing. To save Stratholme from the undead plague, he slaughters everyone in the city, and his dedication to duty is what leads to his taking up Frostmourne and his eventual transformation into the Lich King.

Arthas' corruption affects the entire course of Warcraft's story, including Sylvanas Windrunner's transformation from ranger to Banshee Queen, turning her from loyal defender of Silvermoon to ruthless leader of the Forsaken. If the road to hell is paved with good intentions, Arthas placed most of the stones himself.

Who are your favorite video game villains?