I dont play this game so i could be missing important info but heres why i think this is supposed to be hanfu (inspired) not Japanese (inspired).
The Shape of the necklace style and the prominent use of jade throughout signals Chinese influence. The skirts style of a wide middle pleat and smaller surrounding pleats looks inspired by mamianqun. The top is very reminiscent of some styles of dudou. The waist ornaments too are very yunjian. The sash is also tied in a way ive only seen in ruqun styles.
I also took a quick look at the weapon the girl is based on and ots Chinese so its not really a stretch.
I dont play this game so i could be missing important info--
Its a halloween themed costume, thats really about it. This costume is part of the "Warning! Monsters Incoming!" Halloween batch from 2022 (Based on CN release). Other T-dolls who received costumes for that batch include; Sten MkII, JS 9 (The T-doll in the image here), MG42, M327, PPQ, G43, and KH2002. She could just be donning a youkai or monster appearances to fit the theme, though i'm not too familiar in what she'd based on i'm afraid.
