As with most novels at the start of the series, there is a fair amount of world building. We are first introduced to the Night of Revelations and its impact on the world at large. As we go along we're given more insights into the world at large ranging from the small to the sweeping. It is rather smoothly integrated into the story as a whole.
The mythology of the piece is complex and multi-layered. I found myself wondering many things, such as the reaction of various Hunters to the Revelations. The fact that the Fae are as much a mystery to Riley as they are to us drives that point home fairly severely. It really is a case of there being more things under Heaven and Earth than are dreamt about.
I have to admit, when it comes to the main character, that Irish-Japanese mixes are a relatively common thing for me. Though I've mostly used the combination to create a unique fantasy culture. As such Riley O'Neil is a delight. She quite often shows glimpses of either culture under her otherwise thoroughly American attitudes.
I also begin to wonder if the later books will begin to show Japanese myths coming out. Maybe the Night Parade of a Thousand Demons or the oni of Onigashima. Well. I'll just have to read the other books to find out.