i've done a few character concepts in the meanwhile:
the first two girls wear traditional costumes of the Sakha (Yakut) people of the 17-18th centuries, based on the results of various archeological excavations.
sadly, there is not a lot of concrete information about this period, so the casual costumes on the 1st and 2nd pictures might actually consist of festive clothing (since people were usually buried in their most decorated attire). as of now, the combination of those clothing elements is a speculation of my part, but all of them have their roots in scientific costume recreations
the third picture portrays a magical outfit of a Sand magician.
not all Sakha people used to tattoo themselves, but there is evidence of it existing in some parts of that region (which likely came from the Evenki people). their meaning has been lost to time, unfortunately. they were given to people in the early childhood, which is also unfortunate. that's history for you!
i'm not too sure, if a light hat like that would be worn with a furcoat, but both items used to be an important part of a bride's costume. there is also a furred hat that a bride could wear, so it's hard to say, really. maybe this light hat was worn during summer with sleeveless coat only, maybe it was worn with the furcoat. i'd love to know more for sure, i hope we can still discover more about this period of time!
Sand magicians are a part of Earth magician regiment, and they often work with Fire magician regiment to create Glass attacks. i'm thinking of writing out the way that power-combo system works... or maybe even draw something related to this topic... hmmmm
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the other four characters come from different regions: the first girl is from the north-eastern part of Bashkortostan, the guy next to her is from Arkhangelsk Oblast, and the guy and girl on the last picture are from Oryol Oblast. the Oryol girl's costume is similar in structure to Tasya's costume, where she also has an apron-like cover with sleeves and also a skirt that is cut in half in the front (which allows her to tuck the ends of it into her belt).
all of them are going to be a part of a story, where they (along with Tasya) go to find treasure in a dangerous cave... Tasya will have to save their butts a lot! i hope i'll write the outline for the story soon