Woah that was a long comment. I appreciate it, though, I'm glad to see this... passion I guess we can call it. Also I'm answering in english since your comment is in english but Spanish is also my mother tongue so it may be a bit weird.
Well let's see there's a lot to comment. First I wanna tell you that I don't really like to give all the answers, so I may leave some things open. I prefer people thinking about it themselves. And second: SPOILERS, so for people reading this that doesn't know anything about the story, please avoid!
For the Wolf story, well there's a lot to comment there, I may create a blog entry about it one day but the main point behind it was to recreate what you were reading in the story to a point inside another story. The entire "story that should be true" in a more complex way with certain representations and metaphors. The other characters on the story, like the snake, crow and all that, they are not necessarily people from the "real world", but actually influences in the main character. Each chapter represents certain types of "pressure" the wolf receives, expectations he must fulfill if he wants to reach an objective. The very moment you need something from the world, the world will put labels on you on one way or another, that's why in each chapter the characters try to put a "label" on the wolf. The first chapter, about right and left, represents control, and how Ciar was obsessed with controling everything through lies to be able to reach his objective. The entire complex plan to express his feelings avoiding the risks of his trauma, it is made clear how his plan "will fail" because the sun "has already won", because how right and left, black and white, happiness or sadness, how they are change so brutaly at every given moment during this chapter. Because they are all lies, and with so many lies you can't really control anything.
The second chapter with the snake is about tentations. The vivid colors of the snake, her attitude about being really close and flirty. Those represents tentations on Ciar about going "one step ahead", in this case saying the truth about his feelings. However he knows how tentations can lead to the poison of the snake. There's fear of failing now that things are going well, and at the end avoids the snake just to suffer more and more in his doubts, just because at the end all he wants is to make sure the the moon will be there to run away in case he needs it.
The crow chapter is about relationships, that's why is about a collaboration between the wolf and the crow, how they need each other to get an objective, in this case represented through food. What Ciar is trying to express here is how he managed to make it so far until now thanks to his friends (Ziva, Ausse, etc...). He needs of society to reach the sun, all humans needs of others for everything and nobody is truly fully independent, however what is put in doubt here is how real can this relationships be considered. Is there really love? Friendship? Or is everything just people acting for their own benefit (including yourself)? That's why this part of the story is called Real, and the crow never gives his name. In the previous story it was right or left, warm or cold, in this it should be real or false, but it is never really expressed which one is the correct one. So, are these relationships real or false? That's what the wolf (Ciar) doesn't know. Or doesn't want to know, because he himself may be false too.
There's more to it than just this. The references to Skoll and Haiti, Yagatarasu and some other things, but I'll leave those for people to investigate themselves.
Now, about my opinion for the characters. Let's see, this may take long.
Luce: she's great. I just can't help but love her. I tried to create a character that people would fall in love with. Not so much because of her aspect (that she's pretty sure, but Ziva for example was made more appealing exactly for this reason), but because of her personality. I wanted to create someone that you would fall in love with her a little bit more with each scene. So you first see her and she almost doesn't talk, then in each scene she's more and more brave, opening herself more, and showing how strong she actually is. She's the strongest character in the game, she manages to overcome everything by herself and just by her power of will. However, she still becomes embarassed about showing certain parts of herself, and doesn't really want to to be labeled by other people. In that aspect I took some aspects that actually happen to me to try to make her more realistic and tackle some themes in the novel, to make sure her character is more complete. The final plan was to make sure that you, the reader, fall in love with her, so you can identify better with Ciarán at the end and become overwhelmed when she actually saves you, and not the other way around, changing the usual style romantic visual novels follow where the guy saves the girl.
Ziva: She's pretty, and in this case I wanted to make it as a more perfect character. She's the best in every aspect. She loves the main character in her own way, she's popular, helpful, caring, attractive, she's even good at videogames! In a lot of visual novels and anime one thing that happens a lot is how there's clearly a girl that is better at everything that everyone loves, but the main character goes with someone else for no real reason and makes everyone mad. Here I wanted to defy that in a different way most people would understand: Ziva is perfect, but she's not the most compatible person with Ciarán. I think this is something really important that most creators don't know how to handle. The scenes between Luce and Ciarán are interesting because you can see a chemistry between the two. Sure they insult each other and all that, but it's made obvious how their compatibility is really high, however with Ziva is different. They are not compatible, they can be friends, and Ziva sure, is great, but it's not what Ciarán needs. Her caring aspect is not good for a Ciar that, due to his trauma, can't really accept help from other people, that suffers when people spend their time or efforts on him. Luce is different in that aspect, she even bullies Ciar from time to time, but that's precisely what Ciarán needs. So here comes the point: sometimes the best for us is not "the best" option, but the one that helps us to grow, so even though the story with Ziva ends kinda... let's say... bad, at the same time I think no one really felt as if it was forced, people can relate to how Ziva is great but there's a pit that separates the two that can't be helped. Life is not fair, and sometimes you can't do anything about it.
Ausse: Oh man Ausse is such a great character. He's a character that has survived me some other novels and projects that never actually came to light. The first point was to make him the cliche flirty friend that loves all the girls, and sure he is, but it was all to get to his conclusion and theme at the end. About how the personality can't really be set in stone for someone, how people can decide what to be or how to act depending of the situation and that's not a bad thing. People get obsessed about being "something" or "someone" in particular. I'm personally tired of hearing that "just be yourself" as if "yourself" was actually something. People change all the time, they act differently with different people, and that's ok. Ausse takes that and makes jokes about it, becomes whom he wants to become and helps the main character in his own way. Sometimes people think that you can only be friends with someone when you talk serious or deep themes, but I think a good friend can also be that guy that only wants to make you happy, even if it's just with silly things.