I've thought about it and for now I think that Reimu is Maid of Breath. Her ambiguous situation with parents (they are gone for some reason) and implications that her mindset was heavily influenced by Yukari who was grooming her to be good barrier keeper (between dream and reality). Her mindset is also stated to be similar to one of taosist. It seems that while Breath is her aspect, she has a number of issues with forced Breath and lack of it in regards of her obligations and duty.

Oh, Breath is Reimu’s Aspect like you wouldn’t even BELIEVE, her protagonistic position and her powers? Her power is that of Flight, to the point of literal Detachment and Ascension. And she’s a Shrine Maiden, so that’d fit as well. Also I can’t quite recall how canon it is, but the common fanon of her sort of taking her sweet time to actually go check the incidents and detached demeanor when it comes to solving issues mixes well with this too.