In my WIP, I have what are called Time Watchers. Basically they are the oldest beings in the Omniverse (also called the Universe Primordials) and their jobs are to watch and record events occurring throughout history without interfering (long story short). The most important of these events happens to be centered around the MC and his adventurers.
The only way I think this will work is in third person omniscient. The problem I'm having is that the omniscient narrator is the Time Watcher assigned to that universe and, unbeknownst to the party, they meet.
Would meeting the narrator of the story actually work for third person omniscient? I'm guessing it depends on how I write the story but I want to make sure. I don't want to violate any omniscient ground rules.
You could consider using a peripheral character to be the narrator of the story. An example could be the character Nick Carraway--the first person narrator--in Fitzgerald's novel
The Great Gatsby.
In such stories as the above example, the narrator can or could at times assume to have omniscient knowledge of certain events which logically he couldn't (since he is not a "god", and wasn't there, and was never told about it, etc.)--hence, the term "omniscient 1st person [narrator] Point-Of-View" for those types of stories.
From your brief description, for your story, it is possible that your Time Watcher character could be your "Nick Carraway" and that your MC could be your "Gatsby".
If you search around, either on the internet or on this site, for threads on "omniscient" + "first", and maybe include "Great Gatsby", you'll find discussions on this topic. (Especially here on AW, there are many threads on this.)
Usually, if this type of story structure is used, then the author generally uses 1st person POV. (It is possible to use
limited [narrator] 3rd person POV, but it would be technically much harder.) Note that this type of story POV--omniscient first person POV--could end up being very similar to reminiscent narrator POV, for the reminiscent narrator usually looks upon his past events with omniscient-like abilities. And often, there is an overlap.
(Also, note that the general convention is to consider that "omniscient POV" is short-hand for "omniscient narrator 3rd person Point-Of-View". And that the omniscient narrator is NOT a character in that story--and is not a character at all. And since your intention is to use a character in that story as the narrator, then your story POV would not be considered as an omniscient POV.)
Many creative-writing books on the general craft, or on the specific topic of Point-Of-View, will usually spend twenty pages or more on the topic of Point-Of-View in fiction, and I'd expect that they cover this issue of using a peripheral character or secondary character as the story's narrator--though they might use a different term for that type of POV.