Is it possible to build new structures in a town?

and are these "new alts" planned to be included with the 3 creatures that already exist in the castle? or is it a completely different system? I mean, can't you just use an "improved" building that already exists?

Added 2 minutes ago
ah, is it a system where, for example, you can choose from 7th-level creatures, or a chain like Angel-Archangel-Seraphim, or an alternative like Dragon-Super Dragon-Even More Super Dragon?

Added 31 seconds ago
so there are twice as many creatures?