This is a lovely question and nice food for thought. I thought it would take longer for me to summarize it into one word, but when I thought about the characters I'm working with, their dynamics, and the direction I want to take the story, It became pretty obvious.
Acceptance would be at the core of all the magical happenings and mashups in my comic when I strip it down and sum it up 
Escapism is the basic fundamental quality of every good fictional story, for the writer at the time of writing and the reader at the time of reading.
A good fictional story makes the writer and readers live the events therein, to experience the narrative as if one is right there when the events unfold. Mostly written in ‘show’ and seldom in ‘tell’ helps bring that quality to a good fictional story.
You become the tenth member of the fellowship of the ring. You become the bird that soars above the hobbits as they march to win back their homeland. You sit with the rest in anticipation of Hari Seldon’s next epistle from the past. You swing a mighty axe in the battlefields of Hyboria, and quaff sour ale with the pirates as Belit does the dance of death to ensnare her man. You ride hard with the Rohirrim, you slay Orcs and Uruks. You hide from the Nazgul under the trees with the boys. You cheer with the crowd as Elizabeth scores the winning point. You revel with Moonface in the lands atop the Faraway Tree. You run alongside Roy Race as he unleashes the fabled Racey’s Rocket. You revel in Sheev Palpatine’s malice as he manipulates his way up in life.
That’s Escapism. That which takes you away from the humdrum of reality for a while and makes life worth living. That is the motivating factor (the one word the OP asks for) that drives me to read stories, and to write stories. To write from the ambient perspective of every character in the story, regardless of how big the role is, as the story matters more than the sum of its characters.
Of the two novelized stories that I have on this website, I do precisely that. Escape to another dimension of make believe and fantasy for a while, and hope that readers have the same experience while reading my works as I have had writing them.
Disclaimer – Stated above is in entirety my opinion from personal experience and execution.
I'll probably go with Time -- Like the title itself, Day until Night, the story revolves around with time. Like there's always a right time in everything that happened to my characters.
Like where one's past plays an important role for the story itself and how time will test them for better or for worst., or like what the main lead have said in the latest chapter : "To make everything 'right' this Time"
I see. So in reality it is less about the content of the book and more about the overall way it is written.
Haha my bad, I misinterpreted the intonation of your previous answer and scared myself a little 
thankfully it turned out that way :
You : 
Me : 
Thank you for taking interest in my introspective view of my work, it is nice to hear ! 
I am still not sure about eveything, this piece certainly means a lot to me and I interpreted it in sooooo many ways before actually giving it a definite form and sharing it with people? It is nourished from multiple personal aspects and subjects that I wished to approach all at once, and it ended being confusing as a reader (and frustrating as an author).
But one day, when the right time comes for me and if I decide taking the risk to not keep it private anymore, it should be out in a shape or another, multiple or simple, sooner or later...
we'll see ! 
HHmmmmm, that's a toughie, I'd have to go with eldritch. (its based off H.P. Lovecraft, I couldn't resist!)
Solid topic. 
I think for my first novel, The Faerie Dusters, the word is 'change.' For The Space Bum, the word is 'quest.' For Star Seeders, the word is 'development.'
Interesting, let's see if I can find some proper words for them:
Change The main character of this story goes through just a...massive amount of change in a fairly rapid time, both positive and negative and aside from being a romantic story, was a way to experiment with how someone reacts to various types of change in either direction. Change is something that a lot of people have to deal with and everyone reacts to differently: some people work well with change and other people have a very terrible time with even the smallest of changes. A lot of times however, in this story, the MC who does not have a good time with change, is forced to go through a lot of very, very dramatic and drastic changes in rapid succession.
Atonement Weird word, I know. Atonement means reparations or satisfaction for a wrong doing or wrong deeds, basically, it means making amends for something bad that someone has done. The story revolves around two characters: one who has caused a large amount of wrong doings and bad deeds and the other whom is the most wallflower person I've ever written. It revolves around what is considered needed to be forgiven for those deeds, beyond just an apology and what should happen if one of those deeds is bad enough to the extent where the wrongdoer themself are unable to correct it.
Revenge Alright, this story is one of the ones I had the most fun with: I am a massive fan of all sorts of horror movies, slashers/thrillers/monster movies, the works. I wanted to push the limits to what would be considered "proper" by the guidelines by writing in a style that resulted in almost every chapter being marked "Mature" due to language, gore or the themes that are depicted and talked about in the story. It was also an experiment with having a Bad Guy MC, having a character be by default Bad with no possible way of being seen as a "good guy" among those lines, A Bad Guy that is unapologetically bad and with good reason that...was quite interesting to write including having the Bad Guy character win and the "protagonist" of the story loosing. The MC had a massive slew of bad things happen to them that could not be rectified by the wrongdoers apologizing, so the MC decided "blood for blood" and took it into their own hands. It's a story about all sorts of revenge.
is coming for you
