These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
In both the fandom and the series, one of the most controversial questions is whether Astrid is a troubled but well meaning heroine who tried desperately hard to be the good guy or a manipulative, sanctimonious Icequeen who thinks only of herself, as Sinder put it. Like when she pushed her little brother out a window was she trying to save 200 children and bring back 200 more, or was it a selfish act when she should of been there for her defenceless little brother? Or did she genuinely love and care about Sam or was she just using him as protection? Did she think telling the whole town about Mary's bulimia was so she could get her some support and help and keep the littles safe, or did she do it because she saw Mary as a threat and wanted to distract from her own faults? Debatable stuff. Expect things to get nasty whichever side you come down on .
Did Caine genuinely love Diana or was he just a manipulative dick who used her for sex? Who knows, as it's constantly being contradicted in Caine's POVS. one minute he's thinking about nothing but how beautiful and smart she is and how he wants to marry her, etc, etc, and the next he's dismissing her as a object or pawn, so to speak, with no interest in her emotions or well-being. Either way, it's riled many heated fan debates, especially after the elusiveness of Plague...
Light answers this question quite overtly. It would seem, yes, he sincerely did care for and love Diana.
Was Howard manipulating Orc to get him money and protection, or did he have genuine concern and understanding for Orc?
Fear spoilers; Is Gaia the premature corpse of Caine/Diana's daughter being possessed by the soulless gaiaphage, or is she still human somewhere deep down who is simply a victim?
Was Mary Terrafino euthanized or the victim of divine intervention by the gaiaphage?
Is Drake Merwin a genuinely worthwhile and threatening villain, or has he become more of a joke as the books progress? This question became the subject of much debate in the fandom, especially after the release of Light.
Base Breaker: Try finding someone who's indifferent either way to Astrid Ellison. I dare you.
There are only two types of people aware of Caine Soren; People who think he's a complete Jerkass and are praying he'd just drop dead in LIGHT and those who are completely obsessed with him and want his demon-babies. The people who want him to drop dead in LIGHT already got their wishes...
True, but probably not how they hoped it would come true. Caine died in a complete badass way and actually saved the world.
Broken Base: Whether you ship the Caine/Diana romance is purely a matter of taste. It is by far the most popular ship in the fandom, with a exceptionally large, vocal and dedicated fan-base. It is also by far the most critisized and refuted. Many argue that it's a beautifully-written, moving, complex, intriguing and ultimately tragic ship which brings out the best in both components. Others argue that its romanticized abuse which undermines diana's independence and strength, and that the two were simply manipulating each other start to finish.
Complete Monster: Drake Merwin, a fourteen-year-old, full-blown sociopath. The first book builds him up as he waxes almost poetic on the subject of guns and his love of using them on people and gleefully volunteers to hunt, torture and kill other kids. When he captures a daycare of little kids and infants, he is fully ready to feed them to coyotes if they resist. In the second book Hunger, Drake beats Sam within an inch of his life with his mutated "whip-hand" while grinning the whole time, suggests using razor wires to shred a girl with super-speed abilities to bits and comes close to killing the main villain's love interest by hurling her almost casually into a rock. In the fifth book Fear Drake subsequently teams up with Penny a girl who can cause hallucinations. They slavedrive the pregnant Diana across a desert while causing her to hallucinate things like the baby being a bug and eating its way out. When Diana finally gives birth, Drake and Penny do it again. It says a lot about Drake that he makes friends with the force of pure darkness and has dreams so twisted and revolting that the dream-reader, Orsay, is paralyzed with fear being in the same room with him. Stephen King himself named him on a list of "Most Terrifying Book Villains".
Crack Pairing: Siana gained speed in the shipping world after Sam and Diana both broke up with their significant others in Plauge. Never happened, but its popularity still prevails.
Draco in Leather Pants: Caine and Drake, believe it or not. Even the author has expressed discomfort with the level of fangirling the series' resident psychopath gets.
Ensemble Darkhorse: Considering the series' amount of characters, it shouldn't be surprising. Some examples include Lana's dog, Patrick, Cookie (who showed up a few times in Gone and Hunger), The Artful Rodger and Justin, and that's only a few of them.
Edilio and Dekka own Tumblr at this point in time.
"Funny Aneurysm" Moment: "All we have to fear is fear itself" would become pretty ironic by the release of the fifth book...
Also in the first book, when Caine ponders why his real mother gave him up, Diana guesses that she was "Just a messed up teenager" when she had him...Again, this becomes almost tragically bitter in the fifth book When Diana becomes a more than messed up teen mother herself...
Caine: (leans close to Drake and whispers in his ear) Don't start thinking you can take me down, Drake. You're useful to me. The minute I start thinking you're no longer useful... (smiles and pats Drake on the cheek.)
A case could also be made for Astrid in PLAGUE, though some fans argue that the jerkass bit overshadows the woobiedom.
Nightmare Fuel: Even without getting into some of the gruesome spoiler details, the nightmare scenario of children on their own without any adults around is enough to scare the daylights out of anyone.
Hunger puts Duck through absolute hell, despite being a mostly innocent bystander, so when you have to read the description of this character who you've come to sympathize with being buried alive (from his perspective), it is quite disturbing.
In PlagueDekka being eaten alive by bugs from the inside. It went From Bad to Worse when the only way to save her was for Sam to cut her open while she was still alive with Lana healing her and killing the bugs that crawled out of her body.
Fear provides plenty of examples of this, including Penny's visions to Cigar, the fate of thekids who poofed, and the mutations. Plus, the whole idea of all of the light going out is terrifying.
Poor, poor Diana in the fifth book. And holy shit.
Magnificent Bastard: Caine, to fluctuating degrees. In Gone, he is this full stop. In Hunger, he's really just a tool for the Gaiaphage.Lies sees him desperate, but still quiteintelligent. By Plague, he's definitely recovered, but has a huge dose of Jerkass thrown in. By Fear, though, he's gotten what he's always wanted, so he has no reason to have any schemes in the works. In LIGHT sweet, sweet Character Development ruins this demeanour for him.
Pennyalmost ascends to this rank in Fear. If only it had occurred to her to, y'know, figure out what she was going to do with Perdido Beach once she'd taken over.
Memetic Molester: Drake. In Gone and Hunger, it was mostly just a couple lines he says to/about Diana, but by Plague, he's talking about Brianna enjoying nonspecific torture he's pretending she recieved from him, winking at Astrid while threatening to "come up and play" with her, and fantasizing about what a long time he'll take with Diana when he gets to her. In short, downright creepy.
The Gaiaphage as well. Especially when you consider that he/it is entering a little child's mind and tempting him to come and play "games" with him...
Most prominent in LIGHT, though each book seems to be sadder than the last.
The basic premise in itself is a bit of a downer.
The Scrappy: Zil. It's near impossible to find anyone who likes him. Part of this most likely comes from the fact that he's based on Hitler.
Albert and Toto are this to a lesser degree.
All three have been overtaken by the ultimate scrappy, Gaia. Literally everyone hates her, and the reveal that the girl on the cover of LIGHT is her rather than her mother, Diana, like it was implied it would be, stirred a lot of feelings up with the fandom.
Astrid was this until Fear.
Selective Squick: This series has detailed descriptions of people's bodies being cut open, people being eaten alive, people killing themselves, people giving birth... and yet there's no cursing. At all.
Unfortunate Implications: Sam is never, ever once called out for attempting to force Astrid to have sex with him in plague, by the narrative, fandom or any other characters. In fact, we're meant to sympathise with Sam when he's screaming at Astrid at her for not having sex with him (while she was taking care of her sick, five-year old autistic brother no less). The blame is put on Astrid for being a "prude" and we're meant to despice her for having the audacity to not have sex with Sam.
The Untwist: One of the biggest criticisms of the series is that the cause of the FAYZ ( Little Pete feeling like he was in danger) was too predictable, which is a shame that it came in the first book, given all the other, far more engaging reveals that came later.