My Fan theories based on “Howl’s Moving Castle” by Studio Ghibli, Hayao Miyazaki. Also includes follow-up fan theories for what caused the war.
1) Calcifer is a symbiotic nano-intelligence from a more technological past (original)
One scene shows an instant makeover of the titular moving castle interior using magic, and it is thought we will eventually be able to do similar instant makeovers using nanotechnology. At the same time Calcifer seems bound to Howl in such a way that the latter gains superhuman powers.
The unusual aircraft designs, the king’s clone-servants, and the titular mechanical structure may also point to a more technological past. Such a civilization might’ve faced reactionary attitudes against technology, and the singularity-level technology our PoVs know as magic could’ve be the last straw that brought on centuries of civil war. The reactionary leader would’ve forced the populace to live in what he co