I am asking because we all know that it takes a long time for cubekid to write a book.

So I am wondering what's slowing him down

Hmm... is shards of Aetheria a published book?

No.

So I am wondering what's slowing him down

The transition between noobville and the most powerful city in Eohune isn't exactly easy to write, there are also several rpg elements that needed to be thought about, research to be done about how the world works to make accurate clouds, skies, stuff like that, research about medieval combat, etc