Nada más que perder

This is a review of the whole series.

The premise of this is really interesting; a sociopath gets obsessed with serial killers, kind of his way of avoiding behaviours that would lead him to give in and do bad things to people. It works for some time, he is a seemingly okay, albeit introverted kid. Until murders start happening in his town, so the main character, John, decides to catch the murderer.
But... it's not even a human being, but some sort of a demonic creature that NEEDS to kill to fulfill his needs. Now John needs to use methods that were developed to understand and catch serial killers to deal with the monsters.
Amazing, right?

Yeeeeah. Forgot to tell you that John is a teenager? Now, I am not saying a book about teenagers is automatically shit. Nope. But in general, teenagers are probably my least favourite kind of protagonists. This series is a perfect example of that. Do I want to read about a 16-year-old doing the edgy “I could kill you in 75 different ways”? Eh.
Sometimes John can be interesting, especially in the first few books, but things quickly spiral and by the end, it doesn't even feel like John is anything special. He becomes completely... well, normal, as far as a person who kills demons can be. But really, he isn't so interesting.

Another thing is, basically no characters introduced after book 2 stay around. I understand that the story necessitates John (and for some time, Brooke) going around and meeting new people, but everything resents at the end of every single book.
New place, new monster of the week, new characters. I don't even start caring about anyone, because I know they will go into the void at the end of the book, never to be seen again. It takes a lot of the stakes; what if the characters die? What then? Not like they would be around later anyway.
The relationships form just as quickly. They arrive somewhere, half the town already likes them and wants to help them. Things like food are a problem only nominally; John worries, yet when they need food, it just appears in the shape of some well-meaning local person who feels the urge to feed the drifter youth.

This leads to another problem. The overarching story is not very satisfying. We know the Withered have relationships with each other. We know they have a history, some way they became what they are. There is some power helping them turn into this. But what? What is going on?
Oh, nevermind, new town, new nice church ladies and group of teenagers who just take them in right away.

And then let's just talk about this last book for a second.
Jasmyn is such a damn annoying character, JESUS. Have any of you seen The Babysitter 2: Killer Queen? Jenna Ortega's annoying special girl, unlike the others is exactly how Jasmyn is. With the tacked on trauma and all. Especially insulting after the development of Brooke (who was already getting on my nerves) through the previous books. Just an even worse replacement.

But the “best” was the end. REALLY? It basically dances back on everything. The series is supposed to be super dark and then we end with “AHHHH, you just need to want to change things and magically everything is solved”.

Honestly, I felt like this was a waste of a great idea. It could have been much more inventive, much less annoying, much cooler. But we got this. Almost smart, almost emotionally impactful.
It's an okay series to read, but it did not give what I expected from it and that makes me kind of disappointed.