User blog comment:SayuriDarling/The House of Hades Official Discussion/@comment-3146855-20131010001758

This was by far the deepest book in the series, and based on some of the more series tones and themes, this is no longer  a series for kids. This book also pulls together points from all other books in both series and also has the most character development ive probably ever seen

wow i just went full on english teacher. someone take me to a mental hospital please.

But just kidding. when i read about nico's secret, i felt like i got punched in the chest and it made me say to myself "this just got serious"

it wasnt percy and annabeth falling into tartarus. it wasn't al the the deaths back in last olympian of labryinth. no.

this made me say  this whole series- well actually both- just got serious. its such a serious and touchy subject and i was shocked. this is no kids book anymore. kinda like the darth maul arc in star wars the clone wars- yeah i watched the show, and i loved it, got a problem- both are defining moments, defining them as not really sutible for the age group it was originally meant for. up until now any kid could read it. but now....wow.