Entirely fair, I was uncertain in the first place. Do you know it is? I'll almost certainly upload more of this copyright in the future, so it'd help.
@schule it seems to me to not be a very historically accurate costume. I think adding korean clothes should be good enough. I think it looks the most like the chinese zhijupao, but if its supposed to be set in Korea, it's probably not supposed to be hanfu- although korean traditional clothes are pretty directly descended from hanfu.
This would appear to be 'tsundere day'. The block on the left starts with the standard "It, it's not like I like you or anything!" but there's one kanji after that I can't translate.
......Did she just cut a truck in half with a freaking torpedo!?
I fear for the guy in the truck, but considering he was definitely driving too fast, wasn't on the lookout for people walking the crosswalk IN THE RAIN. I am less inclined to feel sorry for them.
for admins: this is not an oc, it's a mascot made for the software called yumekey
If the mascot isn't used by the project it still counts as an original character for Danbooru, maybe personification. By the way yume-ko is too ambiguous for a character tag, yumeko is a rather common name, so I added your artist tag as a qualifier.