Okay, so for this I just want to have a discussion of ideas. I am trying to create the following:

Storn's Haven (As shown on my Nord map, posted below) is pretty much a whole kingdom carved into a mountain (or rather, extinct volcano) that is made up primarily of granite. It is an absolutely massive mountain filled with not only a huge castle carved into it but individual houses, tunnels, cathedrals and etc. Only about 30-40% is not dug into the mountain and is from the marble mines just beneath the mountain.

If this is all done in a Post Roman age and society, though the specific culture itself is primarily influenced (in my creating of it) as Early Japanese or pseudo Chinese. Given the technology at hand, as well as the guidance of a more advanced race, how might these people do such a feat (what creative and efficient ways could they do this) and how would a culture like this develop?

I will also take any creative ideas or sketches to interesting examples of what it may look like. I want this to be scientifically realistic, because although this is a magical world, my magic follows rules, and can only truly be carried out by these rules. In other words, the Nordins (people of this planet) cannot carry out magic like this willy-nilly, though they are somewhat aided in the mind and body for creating massive structures such as this one (something unique to their race, even more so than ours at times). To use magic, they would have to use it through moss, plants, animals or the earth itself, which pretty much technologisizes it. So please, nobody tell me to just have Gandalf come in and start shooting lighting everywhere.

Also, one more thing. Part of the creation of this city involved one of the Mithralls, (the race aiding the Nordin's in recreation to their society after the Age of Darkness) and this particular Mithrall woman is notable for her ability to draw natural magic simply through dancing. In a mythological sense, it is said that shortly after the Age of Darkness, she danced upon the top of the mountain all night for three days, causing it to crack and for metals, granite, marble, and salt (which breaks down rock and is useful in that sense, and in this day and age is considered extremely valuable) and this would naturally aid the proccess inwhich the Nordins would be able to dig their way into the mountain and create a safe haven.

oh, and Storn's Haven is named after a species of bird that resembles a large raven that inhabits the mountain, if you wanted to know.

So if anyone has some creative ideas or notes of mistakes I should not make (literary holes that would make it unrealistic in a physical sense) please tell me. I love the creativity of these ideas.