First of all, very good work. I'm happy I started supporting you in patreon after finding you here a few months back.
I love the fact that the story got darker with twist after twist. I would definitely read a manga(Even non porny) of this, or watch an anime about it, so that speaks for the quality of the storytelling. Even when the main character actually wants to do most of the things he does, he really is quite literally stuck in-between two messes.
Speaking about the goddess, I do TT Roleplaying with a few friends, and when we play the game where I serve as the GM, I tend to tread the omnipotence of gods and other powerful beings as a sort of "flawed omnipotence". What I mean by this is, first of all, that the gods or beings in question must never be truly absolutely divine. They must have and bear flaws that can range from overly abundant arrogance to naivity.
You can't make tricks and twists that a character does something on the back of someone truly, absolutely divine, cause someone like that, with omnipotence, would always know and stop any and all plans against them or their objetives.
With a god or demon(Or a great omnipotent wizard), what you need to do it make them arrogant enough to not monitor your protagonist or villain at all times, give your protagonist or villain something to avoid the gaze of these beings, or have the being in question be naive enough in their trust that they'll either leave you unattended or trust that something you're doing that looks bad in the moment is actually for something good. Maybe an alternative to all this would be having a chaotic entity like Sheogorath in The Elder Scrolls, who's basically omnipotent in their own way but just gives no fucks about what people do.
The goddess feels arrogant to me, while the Demon king seems naive, so excellent work there too. Hellele look like she's just one of those chaotic entities that have fun and never let you in on the -real- fun and will either screw you over real bad or make you INCREDIBLY powerful cause she wants you to be a champion of sorts and that's that(I like these kind of characters too).