I think the Heartless are some of the most interesting villains in video games. They act as the perfect foil to nearly all of the themes in Kingdom Hearts.
At the center of everything in the game is, of course, the Heart, which sort of symbolizes everything that it means to be a human: emotions, memories, thoughts, and beliefs all seem to tie back into the heart. This is the main source of Sora's power, and indeed means the most to him then perhaps any other character in the series. Love and the desire to be needed is what drives Sora to make friends in all the worlds he goes to. Every time he gives someone a helping hand or even just talks to them, his heart connects with theirs, and that network builds with memories, affection, love, and friendship, IE, the things which Light symbolizes.
The Heartless, on the other hand, experience none of the sensations of joy that Sora feels. The Heart and all its connotations are what mean the most to Sora, and, of course, the Heartless cannot sympathize with this. Indeed, there's almost an overwhelming feeling of mockery in their relation to Sora. When they visit a world, they consume until there is nothing left, by virtue of consuming the heart of the world. And that is surely something that pains Sora: if the Heart is the source of love, then the Heartless have destroyed the love of an entire world, including all the other hearts that were within it. And this complete and total absence of love, feeling, or any emotion at all is what makes the Heartless true Darkness. Even Ansem, or Xehanort, or anyone else who dabbles in Darkness experience some kind of emotion or feeling, and even they can experience the sensation of love, even if it as mean and centered as the love of one's self. The Heartless cannot: for them, they are as far away from the Light as possible because they are completely incapable of any of the feelings that Light provides. They are the absence of love, and surely, when the shadowy phantom of Sora appears on Hook's ship, it is the biggest slap in the face to our protagonist, for that is as feared a version of him as he could imagine.
Also, there is a prominent sense of childhood wonder and dreams in the first game. Sora's going to strange new worlds, meeting new people, and going on an adventure with iconic Disney symbols. He's living out the fantasy that many kids have had at one point or another, and that is, what I think, what one of the main selling points of the original game was. Considering that the movies referenced were released within the time period when the audience would have been younger, it hearkens back to memories of their own childhood, and gets them more emotionally invested in what happens. This is true as well for the cameos made by the Final Fantasy characters. What matters is that these are figures, worlds, and characters that mean something to the person playing the game, and likely makes up some element of their own memory.
When the Heartless appear in these worlds, they are threatening to destroy those memories and adventures. Not just Sora's, but those of the audience as well. The Heartless aren't just going after faceless NPCs: they are going after people that the audience knows, has emotionally connected to in the past, and perhaps are even fond of. This is especially prevalent if we consider once again the importance of emotion. What made classical Disney great was that it knew the emotions of a good story, and all the best moments in their movies come from garnering some kind of emotional reaction from the viewer. But once again, the Heartless are a vacuum: no feelings reside in them, and any emotion that they come into contact with dies. Introducing entities of non-feeling into a universe of movie history where love and feeling are presented as universally important make the Heartless a unique threat.
Worse than that, they are more than capable of making good on that threat. We know that they successfully destroyed the worlds of Sleeping Beauty, The Lion King, Mulan, and, if the depth of the End of the World is to be believed, they have been doing this for a very long time and have gotten very good at it. It's what makes them more frightening than, I think, any other rational-thinking villain in the series. Xehanort can plot and plan well enough to carry out his schemes, but the Heartless are capable of mass murder without having to even think about it. They don't need a plan: that kind of large scale destruction just comes natural to them. They are so beyond the average human's ability to cope with: they don't need to fight the toughest guy in town. They just need to find the heart of your world. And once they do that, it's game over. The ability to essentially negate and nullify the defenses of nearly every world, as well as having access to the killswitch of your existence, is what makes the Heartless the kind of threat they are.
And something that I really love about their role in KH1 is that everyone who uses Darkness thinks they understand. Maleficent, Riku, and even Ansem all think that they get the Heartless, and that they can be controlled. But, of course, they can't. It's the best piece of irony: for all the antagonists long term planning and scheming, the mindless Heartless manage to outsmart all of them. Because they don't need to act: they simply have to wait as the villains give in to their anger, frustrations, lusts, and sins, which all eventually lead to their downfall. The Heartless do not blunder like their would-be masters, because they can't feel these emotions. They don't let their pride nearly drive them to the brink of destruction, or let their greed cost them, or let a misguided sense of righteousness lead them to their final demise. They can wait, and as we see at the end of the game, they outlast all of the villains, and come more close to Kingdom Hearts than any of them ever did.
And with all this in mind, the real importance of the Heartless is, ironically, in highlighting the boy that would stop them. If the Heartless are the objects of this much power and fear, it makes it even more important that Sora stop them. And why can he stop them? Because Sora can understand the one thing that the Heartless can't. Sora can love and experience emotion, and it is that desire to keep on feeling that makes him such a potent force against the apathetic Darkness. Sora has seen the Heartless destroy his world, twist his best friend, put Kairi in a coma, and steal from him his past and home. Sora doesn't want to see this travesty happen again, and it is because of that that he will go through the lengths he does. He doesn't want to lose his friends, his memories, or his ability to love and be loved, and when he says that his friends are his power, he means it quite literally.
He is the last, best hope for keeping the Heart and all of its emotions present in the universe, and that is why the Keyblade chooses him as its best bet to stop the Heartless and save the world.
I think the Heartless are some of the most interesting villains in video games. They act as the perfect foil to nearly all of the themes in Kingdom Hearts.
At the center of everything in the game is, of course, the Heart, which sort of symbolizes everything that it means to be a human: emotions, memories, thoughts, and beliefs all seem to tie back into the heart. This is the main source of Sora's power, and indeed means the most to him then perhaps any other character in the series. Love and the desire to be needed is what drives Sora to make friends in all the worlds he goes to. Every time he gives someone a helping hand or even just talks to them, his heart connects with theirs, and that network builds with memories, affection, love, and friendship, IE, the things which Light symbolizes.
The Heartless, on the other hand, experience none of the sensations of joy that Sora feels. The Heart and all its connotations are what mean the most to Sora, and, of course, the Heartless cannot sympathize with this. Indeed, there's almost an overwhelming feeling of mockery in their relation to Sora. When they visit a world, they consume until there is nothing left, by virtue of consuming the heart of the world. And that is surely something that pains Sora: if the Heart is the source of love, then the Heartless have destroyed the love of an entire world, including all the other hearts that were within it. And this complete and total absence of love, feeling, or any emotion at all is what makes the Heartless true Darkness. Even Ansem, or Xehanort, or anyone else who dabbles in Darkness experience some kind of emotion or feeling, and even they can experience the sensation of love, even if it as mean and centered as the love of one's self. The Heartless cannot: for them, they are as far away from the Light as possible because they are completely incapable of any of the feelings that Light provides. They are the absence of love, and surely, when the shadowy phantom of Sora appears on Hook's ship, it is the biggest slap in the face to our protagonist, for that is as feared a version of him as he could imagine.
Also, there is a prominent sense of childhood wonder and dreams in the first game. Sora's going to strange new worlds, meeting new people, and going on an adventure with iconic Disney symbols. He's living out the fantasy that many kids have had at one point or another, and that is, what I think, what one of the main selling points of the original game was. Considering that the movies referenced were released within the time period when the audience would have been younger, it hearkens back to memories of their own childhood, and gets them more emotionally invested in what happens. This is true as well for the cameos made by the Final Fantasy characters. What matters is that these are figures, worlds, and characters that mean something to the person playing the game, and likely makes up some element of their own memory.
When the Heartless appear in these worlds, they are threatening to destroy those memories and adventures. Not just Sora's, but those of the audience as well. The Heartless aren't just going after faceless NPCs: they are going after people that the audience knows, has emotionally connected to in the past, and perhaps are even fond of. This is especially prevalent if we consider once again the importance of emotion. What made classical Disney great was that it knew the emotions of a good story, and all the best moments in their movies come from garnering some kind of emotional reaction from the viewer. But once again, the Heartless are a vacuum: no feelings reside in them, and any emotion that they come into contact with dies. Introducing entities of non-feeling into a universe of movie history where love and feeling are presented as universally important make the Heartless a unique threat.
Worse than that, they are more than capable of making good on that threat. We know that they successfully destroyed the worlds of Sleeping Beauty, The Lion King, Mulan, and, if the depth of the End of the World is to be believed, they have been doing this for a very long time and have gotten very good at it. It's what makes them more frightening than, I think, any other rational-thinking villain in the series. Xehanort can plot and plan well enough to carry out his schemes, but the Heartless are capable of mass murder without having to even think about it. They don't need a plan: that kind of large scale destruction just comes natural to them. They are so beyond the average human's ability to cope with: they don't need to fight the toughest guy in town. They just need to find the heart of your world. And once they do that, it's game over. The ability to essentially negate and nullify the defenses of nearly every world, as well as having access to the killswitch of your existence, is what makes the Heartless the kind of threat they are.
And something that I really love about their role in KH1 is that everyone who uses Darkness thinks they understand. Maleficent, Riku, and even Ansem all think that they get the Heartless, and that they can be controlled. But, of course, they can't. It's the best piece of irony: for all the antagonists long term planning and scheming, the mindless Heartless manage to outsmart all of them. Because they don't need to act: they simply have to wait as the villains give in to their anger, frustrations, lusts, and sins, which all eventually lead to their downfall. The Heartless do not blunder like their would-be masters, because they can't feel these emotions. They don't let their pride nearly drive them to the brink of destruction, or let their greed cost them, or let a misguided sense of righteousness lead them to their final demise. They can wait, and as we see at the end of the game, they outlast all of the villains, and come more close to Kingdom Hearts than any of them ever did.
And with all this in mind, the real importance of the Heartless is, ironically, in highlighting the boy that would stop them. If the Heartless are the objects of this much power and fear, it makes it even more important that Sora stop them. And why can he stop them? Because Sora can understand the one thing that the Heartless can't. Sora can love and experience emotion, and it is that desire to keep on feeling that makes him such a potent force against the apathetic Darkness. Sora has seen the Heartless destroy his world, twist his best friend, put Kairi in a coma, and steal from him his past and home. Sora doesn't want to see this travesty happen again, and it is because of that that he will go through the lengths he does. He doesn't want to lose his friends, his memories, or his ability to love and be loved, and when he says that his friends are his power, he means it quite literally.
He is the last, best hope for keeping the Heart and all of its emotions present in the universe, and that is why the Keyblade chooses him as its best bet to stop the Heartless and save the world.