I was thinking the same thing as
@MemoryTale above. There seems to be a pretty uneven power balance between the beings you mentioned, so one would presume an elder god/divine being would be the clear cut winner. You know, the whole "seeing his face will drive a man insane/cause him to burst into flames/[insert gruesome death here]" thing...
I do want to reinforce a couple points made earlier. First, setting is very important, but it won't sell books or pull in readers. Books don’t have a visual component, so you cannot rely on great special effects and fancy locations to cover for a lackluster story (*cough*
Avatar *cough*).
A book is something like a person. You have background information and setting are the clothing your story wears, but it is the characters who make up the core of the story. Imagine
X-Men without Professor X, Jean Grey, Wolverine, and Cyclops, or
Deadpool without Deadpool, or
Star Wars without Vader. It is hard to do, isn't it? If you can, you may not enjoy the results very much. This is because characters and their actions are what drives the story, and the setting is more or less just a context for their actions.
That is not to say, though, that a well developed setting isn't important. Far from it! Who doesn't remember the X-Wing, the Death Star, or Tatooine? But, if you changed out the X-Wing for, say, a Viper from Battlestar Galactica, you haven't really changed the story that much. Same for the Death Star; you could swap it out for any number of world ending cataclysmic creations and not change the story around much. But, if you sub out Darth Vader with Cylon #6 or Luke with Apollo, you have an entirely different story.
Also, glad to see you posted for the Writing Challenge! I actually joined this site specifically for the Writing Challenges, because I knew I needed to improve but didn't have any local avenues to do so. I can say that I have improved immensely as a writer through doing so, and when I write complete feces, I have a group of people and a place to ask what made it feces and how it could stink less. And, at 75 or 300 words, it isn't so painful when the product is feces.
Which is another point I want to reinforce. You
will write garbage. We all have and do more often than we really want to admit. What I submit to the challenges is often garbage enough, leaving aside the rejected ideas and early drafts which aren't suitable for public viewing. And even when you strike gold, it probably won't be recognizable at first with all the dross that needs to be refined out through editing. The only real question is how much garbage will you write until you start finding some gold (and perhaps making some gold as well...). Seriously; if you saw some of my early attempts three versions of my universe back, you would tell me to step away from the keyboard before someone got hurt. So, you will fail. You will make mistakes. You will write things that threaten to summon eldritch abominations should they not be purged immediately from your computer (ok, maybe that one is just me...). You will get ripped apart by critiques and have people not like your work, and when you come back with an edit, find more faults. What of it? Being able to preservere through the challenges of writing and editing (and editing and editing and editing and...) is what separates aspirational writers from published ones.
But, you needn't worry about all that right now, as you have two key advantages to develop your skill; the community of this forum which includes many published authors, and the writing challenges. The former gives you the ability to have charitable (well, mostly charitable; I can be a bit of a jerk at times) individuals filet your story exerpts and give expert opinions on them. There are some (myself surely exempted) whose opinions are worth their weight in gold, and you will quickly learn who they are. The challenges will give you the chance to play around with new things while refining your editing skills. If people don't vote for it, don't get mad; the best thing to do is put it in the improving thread and see what people say.
The two things I would add to the advice you have been given thus far is to define your ideal reader and decide what you are trying to write. The former is important because you are going to focus on different things depending on your audience. For example, as man in his 30s with two young kids, the situations I would resonate with are entirely different than the ones I would have resonated with in my teens. Depending on what you are planning to do with your story, this may have some effects, but there is some wisdom in keeping your prospective reader in mind as you write.
For the latter, you need to determine if you are interested in exploring a theme, a character type, a storyline, or are just looking for an action packed book. It sounds to me like you are going for a cross of
Street Fighter and
Supernatural. Nothing necessarily wrong with that, but your execution would be completely different if you are looking to explore the futility of resisting destiny or looking to explore divine uppercuts and roundhouses, both of which would be different from corporate satire.
So, I would start with identifying what sort of story you want to write to whom. Then, build the universe, characters, and storyline to serve that purpose. In all likelihood, the rest of the details will follow from that. But, in the meantime, don't be in a rush to come to all your answers; enjoy the discovery and invention process.
Oh, and welcome to the Chrons! Only a handful of us bite regularly, so feel free to ask if you have questions.