This city is not exactly under the earth. They just have a different time. Same as winter when the day is shorter and night is longer. Because of this unusual time people keen to call it Underworld.

Before some 'incident' the city is open for everyone but after that, their Archon (Camilla) decide to put some of the strong Layer that cover her whole region.

*She is strong like very very strong*

So now, when you want to go to Naferanam you have to pass a gate/portal that is quite guarded by many guard

This is the gate:

The whole region of Naferanam is huge. The demons in Naferanam is also have many kind. There was a demon that live underwater or in fire or they usually life so close to nature. Base on that, the city is kinda a mix between them.

The city:

A little bit on city inside:

.

Yeah. The city is super huge. Much more than Mondstat and because of that Naferanam is actually the richest from whole Teyvat.

Not by term of Mora but by term of unique stone that usually been make into a very precious jewelry and they also have a kind of flower that sprout a precious pearl. This flower can only grow in Naferanam.

The Castle in Naferanam is actually more than one but this is the castle that their Archon live or should we say the main castle. It also quite close to the city.

They still maybe 4/5 regions that we not yet to explore but for now this city will do.

This Author cannot find the place that exactly look like Naferanam. So this is the close picture of my imagination. Do forgive me (◍•ᴗ•◍).

As the story progress, the picture of each place will be placed so you don't need to work your brain just to imagine how the place look like. Take it as compensation for my incompetent.

Maybe this all about Naferanam. Is there any question, feel free to use comment section.

Bye~