What makes a great RPG? Is it the art style? The musical score? The combat system? As far as I'm concerned, it is the story. Well, the story and how it is conveyed. Those are two very different things. An average RPG will tell you outright what is happening and give you a few characters to move around the game's world like chess pieces. An excellent RPG will use its characters to echo the size, scope, and central themes of its narrative. To that point, I assert that the best RPGs will feature a large and dynamic cast of key or main characters with various motivations that reflect the challenges or schism of their world(s).
Regardless of the variety of RPG that strikes your fancy, characters set the tone. Often without recognizing it we derive so much knowledge of the worlds we immerse ourselves in by spending time getting to know and understand the individuals who are subject to them. You can see this in JRPGs, Western RPGs, Tactical RPGs, and more. It's not specific to any RPG subgenre.
There may be a few key differences in how various RPG subgenres approach game design and plot progression, but all of the best examples of each sub-genre feature rich characters that lead to pivotal and often memorable in-game moments which in turn make the stakes of the story, the complexities/conflicts of the world(s), and the themes at play much larger in scope.
Why exactly was Final Fantasy VI such an epic RPG? A vast majority of us would likely agree that it has a lot to offer. The combat is classic, skill progression is fun, the explorable areas are varied, and I'm not sure many could take issue with how it looks or sounds. There's quality to this product. But, again, why is it an epic RPG? Why does its world seem so big and hold so many stakes? Is it possible that the general narrative of Final Fantasy VI is made bigger by how its varied characters demonstrate the gravity of the game's plot?
Think about the inciting incident. A thief with a heart of gold rescues a witch who is being hunted by an oppressive, technologically advanced empire. Terra has burned both people and places to the ground as a slave of that empire. That power is revealed to be the result of a union between human and mythical beast. Without having to spell things out to the player, Final Fantasy VI presents Terra's character as a walking microcosm of the division between rebel and empire, the supernatural and natural, and technological advancement and magic. Thirteen other playable characters (as well as a handful of key NPCs) represent similar thematic elements and differing ideological perspectives. Each character demonstrates a different portion of the meaty pie that is Final Fantasy VI, and I would argue that the game is only a satisfyingly complex epic because its characters and their individual development build out the game's context on another level.
Similarly, I know many of us enjoyed The Witcher III: Wild Hunt. It's a completely different kind of RPG, focused squarely on the events of one character's travels. Still, Geralt of Rivia and most key NPCs did more to round out the world than the events of the game. I honestly wasn't too engaged in the experience until I interacted with the Bloody Baron. For the uninitiated, this quest forced you to dig through the personal troubles of a family in crisis. The player personally investigates a tale of domestic violence, substance abuse, and the accidental termination of a pregnancy. Given the medieval/fantasy setting of this world, you can probably imagine how simultaneously tragic and gruesome this particular quest was. What I found to be most striking though was not the outcome or the spoils I gained from assisting the Baron, but the humanity and complexity poured into each of the characters involved in this scenario as well as how representative their plight was of the world of The Witcher III: Wild Hunt. This is a land of mythical beasts and brutality, yet the darker side of the game's world is one of human brutality and unrequited desires. That adds layers to the game and really enhances the experience.
We've looked at a few examples of epic RPGs with strong casts, but what do RPGs with weak casts look like? Mostly unmemorable. Do you remember the plot of The Last Story? Probably not. I'd argue that a big part of the problem is that The Last Story is a classic tale of "the chosen one" navigating through a world of political intrigue. The game's focus left little room for exposure to secondary or supporting characters, opting to center mostly on the protagonist, his best friend, and a princess. Ultimately, this meant that the player's understanding of the world's challenges and stakes would have to be limited in scope. It doesn't feel like an epic RPG. It feels like an on-rails, linear story that doesn't waste time on things like character or context.
Kingdoms of Amalur: Reckoning was another title with fairly tight game design and no characters worth caring about enough for the game's stakes to feel important. Like many open-world RPGs, Reckoning focused on engaging combat and generating a large world for the player to explore. In those respects, I'd say that the game was a great success. The only problem is that worlds tend to feel empty if the only characters you meet are about as one-dimensional as a cardboard stand-up. I've told a fair share of people that I thought this RPG was pretty decent, but if you put a gun to my head I couldn't tell you what the story was about or why I was even questing.
It's no secret that games are made greater with better developed and dynamic characters. The point I'm trying to get a though is that they approach taken to character design and presentation can ultimately be the difference between a good RPG and a truly memorable RPG. They don't just contribute to a video game's story as a set piece; strong, varied characters with interesting personalities, ideologies, and perspectives can make any kind of RPG epic and impactful. It's important that we know whom we are playing as and what they have to deal with. Otherwise the game and the player will just be going through the motions.