If Teyvat exists in the Star Wars universe, my best bet it will be located within the Unknown Regions, since it is the only major area in the galaxy that is unexplored, but if not the case, how will Teyvat will handle such conflicts as the Clone Wars, Galactic Civil War, and the First Order-Resistance War?
Not to mention that if discovered, will it be part of the Galactic Republic or not?
It'll be the culmination of how technologically advanced a nation like Snezhnaya is to the world. From Ruin Machines, to Clockwork Meka, to Landcruisers, to ultimately these machines. They would be a tough enemy to face, and most likely require the Snezhnayan-based ability to counter them.
Since Columbina represents the Moon, and with the recent news of Sandrone's elemental origins, do you think we'll meet a Sun or Star equivalent of Columbina, in order to balance her out in terms of power and lore?
Basically the Harbinger's form is the polar opposite of the Foul Legacy Transformation Childe uses; Instead of learning it from harnessing and mastering the powers of the Abyss, they obtain this form from harnessing Celestial energy and mastering them.
The design of the form could be a stark parallel to it, as the Gold, Bright, and Angelic themes run opposite to Childe's Purple, Dark, and Abyssal themes as well.
That and I hope the boss will be a nice callback to the first harbinger boss we've fought, with multiple phases, similar attacks to Childe but on a larger scale, showing how far we have come since we started the game.
(DMC4's Alto Angelo for Reference)