I know the author tried her best, but this is just not a good book. While I understand that all modern Hades and Persephone stories are retellings of the original myths, this follows the myths only on the surface.
Hades is NOT a Greek parallel to Satan. That is a completely modern interpretation, one that would have been foreign to the ancient Greeks. The ancient Greeks didn’t really worship him much, not because he was considered to be evil, but because they didn’t want to draw his attention and be taken away to the Land of the Dead. Since he’s not a parallel to Satan, he’s never described (to the best of my knowledge) as being remotely snake like, having power over fire, eating dead sacrifices whole, or ruling over an evil realm full of demons. The Underworld is not Hell, despite the many descriptions as such in this book. The majority of the underworld was originally described as peaceful and even beautiful, other than Tartarus (which only the worst would go as well as the Titans).
His personality in this book needs work too. He’s a complete sarcastic jerk that takes pleasure in scaring and intimidating people. The Hades of the original myths is described as being solemn but a fair ruler of his kingdom and a just judge of the dead. He also is not the god of death, reaping every person and taking them to the Underworld. That would be Thanatos.
Cerberus’ description in this book is probably the worst I’ve seen from any book. It was extremely creepy and honestly border-lined on racist. Persephone was pretty much just a run of the mill manic pixie dream girl that only wanted to go to the Underworld (not Hell) to get back at her parents.
I hate to give a bad review because I know the author put a lot of work into this book, but it’s really really bad. There are other interpretations of the original myths that stay in line with the source material much better.