I am not a writer, but I often think about this nonetheless.
I actually came up with a basic idea for a plot (but I don't think it'll ever see the light, as I am no writer).
The plot revolves around the protagonist wanting to achieve immortality (then I would've liked to add some personal trauma behind his goal, just to give his character depth, or made him based around me, as I actually have thanatophobia).
The trick is that, often, characters as such, are depicted as evil, as becoming immortal is seen as unnatural and wrong, while this character is definitely not. He actually has humanity best interests in mind with his goal, but nobody understands him, because they all like to live like cattle in a slaughterhouse.
The plot would proceed by having the protagonist witness to some kind of eye-opening event, that actually sets him on his journey, by making him realize humanity's actual power. It just came to my mind that this could just be the result of personal study, that led him to talking with a God, or something along those lines.
The technicalities of achieving immortality would just be allegories to the Magnum Opus.
At some point in the plot the protagonist would unavoidably have to fight an organization, made up of billionaires and politicians, who have a goal similar to his. They too want to achieve immortality, but instead of going through the spiritual way (Magnum Opus) they try to bend the laws of nature with science and robotics, creating monsters, especially as they experiment on kidnapped homeless people (or something like that). Also, they want it only for themselves, using the excuse of overpopulation.
I didn't think about the details of how could this character alone fight this powerful organization, maybe he naively gets recruited at first but then realizes the horrors happening and destroys them from inside, or maybe he has to go the "covert terrorist" route, I don't know. Haven't thought that far. But I like the idea of portraying the conflict between the spiritual immortality based on enlightenment and secret Soul power VS the unnatural immortality based on genes manipulation and robotics, with no intellectual enlightenment whatsoever.
I want the reader to realize that immortality isn't a curse, it is only when approached the jewish way, with no intellectual enlightenment.
Anyway, there could be either a bad ending or a good ending, but for predictive programming it's probably better to have a good ending where the world is freed of this organization that keeps humanity mortal and retarded by the protagonist, who then goes on to create an enlightened society, that manages to get in touch with the Gods that inspired the protagonist himself (if that element has been introduced). It could also be cool to not have the Gods existing in this story, but making it like the ending is the birth of the first generation of Gods, who would then go on to spread life through out the universe.
This last bit was inspired by a strong curiosity of knowing Father Satan's past. We don't know much of how Father became Emperor of Orion, who were His and Baalzebuul's parents, etc. I would love to know more. If the story gets developed with the "first generation of Gods" ending planned, then the protagonist itself might become a tribute to Father Satan, while not daring to be a biografy, just a tribute. Although, this route is probably less useful in awakening our actual fellow humans.