This novel is near perfect.
From story to character design to everything.
Definitely not one of those cliche plots overflows with only cute girls, harem and interpersonal relationship based upon superfluous kindness.
Some philosophical arguments raised by the characters are thought-provoking.
The conversations between the characters contain many useful information and the elements of its mysteries are able to get our brain cells working.
Anyone who is interested in light novel with a postmodern background or mystery-lovers can certainly not miss this.

Ok, overall, to conclude the greatness of this novel, there's only one thing I need to mention......

The siblings love between Demon and the Queen. <3

One of the BEST novels I have ever read. Enough said.