--------THEORIES ------------
Faces (or lack of a face) and water are very important things in the story. The world outside the box is related to the five kingdoms and their lakes. A lake is a reflection of its ruler (that will tie into Myrddin's origins and why he was created). Currently, there are only four domains since the fourth one was destroyed.
Additionally, there are some encrypted messages and easter eggs in the game. However, I wasn't able to go through all the details and secrets in it.
### Entity:
He is the silhouette and the creator of Myrddin. Myrddin was supposed to be a reflection of the Entity/book/silhouette, but the process didn't work completely. The first book Myrddin mentions talks about him, and it is the same book referenced in the encrypted message, where we learn about the Entity/book/silhouette and how it was clear what he was because of "his eyes, his nose and his mouth." Exactly the features that Myrddin does not have, which further confirms that he is a failure.
Note: this information is in "The Song in the Depths" and the encrypted message in the game files.
Ebys seems to be the name of the inhabitants of the depths. The Entity/book/silhouette is not considered an Ebys but rather the "child of both worlds," which matches the fact that Myrddin needs the player's interaction to get power or energy, even though he is not part of the player's world. Myrddin was supposed to be that same child of both worlds, but he is defective. As we can see when we talk to the Entity/book/silhouette, he is way more powerful than Myrddin, yet does not need interactions to get his powers.
- But why would the Entity/book/silhouette create Myrddin at all?
In "The Song in the Depths," each lake was a monument to its domain, something the rulers were proud of. Similarly, the Entity/book/silhouette created Myrddin to be his reflection.
In "A Deal Struck," the Entity/book/silhouette was compelled by curiosity to strike a deal with a mysterious figure, who ended up tricking him. The process of creating a reflection didn't go according to plan.
- But why doesn't the Entity/book/silhouette simply destroy Myrddin?
As mentioned before, the Entity/book/silhouette is driven by curiosity but doesn't want to endanger reality or a large portion of people, so he keeps Myrddin stuck there and conducts his experiments. Perhaps the Entity/book/silhouette also has some kind of unconscious attachment to his creation, though it's hard to say with certainty for now.
- And why would the Entity/book/silhouette care about humans being destroyed?
Once Myrddin is released, he could end up destroy a whole domain.
In many of our interactions with the book, the Entity/book/silhouette says that he sees himself as an evil that needs to do good. Going off that idea, perhaps he feels his actions of destroying a domain were necessary to balance the world. Notice that he didn't destroy all domains; he destroyed one, but four remained. He certainly had the ability to eventually destroy them all, but he didn't, although he left the other domains in terror.
However, another possibility is that the mysterious formally dressed figure who appears in "A Deal Struck" is silhouette... He appears as a very powerful figure, but since the book was first introduced to Myrddin when he first came to the box, the book that talks about the silhouette may actually be talking about the Entity/book/silhouette himself, as mentioned before. Further supporting this is the fact that the mysterious figure's face is concealed with bandages, which goes against what the silhouette is known for: showing "his nose, his mouth and his eyes," the very traits that distinguish him from being an Ebys.
### Myrddin:
Since Myrddin is a "failure", he is not completely a "child of both worlds,"(from the song in the depths) meaning he does not get energy or power from the second world (the player's world) to be strong enough as an entity. He is different from the Entity/book/silhouette. Therefore, if released, he might be dangerous to the world; not being stable, he might absorb the energy around him to compensate for the fact that he cannot naturally produce or absorb energy by himself, unlike the Entity.
That is why he is so dangerous to the depths (name of the world outside the box) and why it is a risk for Myrddin to go outside. But that also means the player is very powerful, since the we are able to provide that energy for him. That is why it is a real risk for the player to be there, and why the Entity is worried about us being there.
However, it is not completely clear why the Entity tortures Myrddin. Since Myrddin doesn't have energy by himself, perhaps the Entity is testing how much of his own energy can regenerate himself, and how that works in his body, given that Myrddin is fundamentally different from the Entity.
### The box:
It is probably inside a lake in the depths, the world of the game. We were able to see an early version of this magical structure that Myrddin is stuck in when we saw "A Deal Struck." Myrddin's story, The Entity stored Myrddin in the box so he could be isolated from all other beings in the depths, preventing him from absorbing their energy or posing a risk to them.
However, since the player is stronger than that, we are able to free him. Perhaps that is what the formally dressed mysterious figure wanted all along, making that figure potentially the main villain of the story.
### Endings:
Aside from the early endings in which the player can simply give up on interacting with Myrddin, there will likely be at least two main ones: freeing Myrddin or not freeing Myrddin. There might be slight variations depending on whether we were honest and trustworthy with him. I'm assuming that if we trusted him and promised to help him, but then decided against it out of fear of destroying the depths, he will be particularly affected by that.
Perhaps this main moral dillemma: help someone who genuinely just wants to live a life without being tortured, or keep him stuck there because he poses a risk to the depths, not through any fault of his own, but simply because he is, as the book puts it, a "failure."
Perhaps there might also be an ending in which we convince or change the Entity, or perhaps even defeat him, so that the Entity no longer tortures Myrddin and his life inside the box becomes a little more "enjoyable"... Or at least somehow expanded. Which is probably unlikely to be such a better situation for Myrddin, though. However, the game might have a canonical ending, so we will have to wait and see what state of the world is actually referenced in possible future stories, if there are any.
The game folows Freytag’s Pyramid, so chapter 4 will be the "Climax" of the story. Meaning, our main strong choices regarding both the Entity and Myrddin wil be there.
Anyway, those were just theories... Game theories! Thanks for reading.
Note: Myrddin calling out those who theorize:
XD