1. Faulty World Logic:

One of the biggest challenges when creating a fantasy setting is defining the rules of the world. In a real world setting, the writer already has this taken care of. But a misconception is that just because the world is based in fantasy that things don't have to make sense.

If in the first 10 minutes the story declares that only Orcs can use magic, then having every single race cast spells two hours in is an example of lazy writing. One of the hallmarks of a great writer is being able to create a universe or setting that stays consistent in the rules established.

Each Harry Potter movie did a good job in showing how the world works. By taking place in Hogwarts, it allows both the main characters and the audience to see firsthand the rules of the setting. How potions work, spells are cast and the laws of the society for example.

Now, setting up world logic doesn't mean you have to explain how everything works to the audience, only the relevant parts matter. For example, I'm a huge fan of the works of Miyazaki and one area that his movies excel in, is the setting. Each movie takes place in a completely unique setting with its own rules, laws and people. The stories never truly explain how the entire world works, only the parts that fit into the narrative and character’s lives.

In Howl's Moving Castle, Howl knows a number of people from before the events of the movie, but the audience is never told just exactly how he knows these people. Instead, we find out their motivations for how they respond to Howl in the present and how it affects the world.

With that said we can turn out attention to Diablo 3 for this point. The problems with Diablo 3 are that the logic of the world is never really explained or fits with the narrative.

First off, it's never made understood why returning enemies: The Butcher, Izual, and The Skeleton King were brought back to life after being defeated in previous games. Diablo gets a pass for being reborn in Leah's body, but it's to our understanding that once a demon is killed, they're gone for good.

Speaking about the Skeleton King, his whole appearance in Diablo 3 is full of plot holes. Why is he a ghost for the first encounter? What happened to the person he cursed? And why is the crown so important to defeating him?

What was the entire point about the sin hearts, and why were there only two of them? The game throws different objects and people into the story, but they're never explained why they are important. What exactly did the catapults do that would turn back an entire army of demons for instance. Or why we needed to save the angel of hope.

The more plot elements that aren't explained, leads to plot holes and logical inconsistencies that can ruin a story. What's worse is that if the back-story of the world isn't set, it can lead to the writers adding more layers to an already shaky foundation, which takes us to the next point.​