Creating a utopian tyranny covered by a firmament

300 years ago, a man named Caesar founded the city of Millennium to protect the Lord's Chosen, all the strong people and the weak people from the God's Plan, which consists of the Great Atomic Holocaust, Comet Eurydice, Wrath of the Sun, the Deluge, Pestilence of the White Plague and Geological Shift.

The city of Millennium is a underground city that spirals downwards 3000 kilometers into the earth, the top is covered with a massive transparent dome known as the Firmament which allows sunlight to enter the city.

Today, Arcam is inhabited by people who are socially stratified, divided between the strong and the weak. Hierarchical levels determines your classes and people if strong enough, can reach higher levels, escaping from their classes.

So the there is a big hole in the ground, thousands of kilometers deep, and at the bottom is a transparent dome that makes it pretty much impossible to climb or fly out of it?

Well, I suppose gardening is going to be very important. It's like a greenhouse in a pit then?

Seems like someone was playing Shin Megami Tensei IV.

If you're serious about writing this story, I recommend changing a lot of things to avoid plagiarism.

No, the dome is placed on top of the hole, troper above And what things do I need to change to avoid Shin Megami Tensei IV, in which I like about the story and settings.

Removal of the religious ideas might be a good start, maybe something a bit more "human"

I'll change that into the Genetically Pure and the Cataclysm.