Fetish Retardant: "Common Knowledge" in-universe has it that Cairax was zombified when he was having oral sex with zombie Jessica Alba. Ultimately set straight by Hale, who maintains that he "just" slipped her a little tongue.
Rodney / Legion also uses an undead superheroine for sex. Goes well and beyond past Squick.
Smith contemplating necrophilia because Corpse Girl is eternally young.
Foe Yay: Smith mentioned being tempted to use Danielle once or thrice for old times sake.
Harsher in Hindsight: The fact that Stealths father was an international terrorist explains where she got her skills from.
Cerberus' comments about her casual sex with Agent Smith become rather squicky when you find out from Smith's backstory that he had used his persuasion powers to instigate the sex, essentially raping her without her even realizing. Made worse when he makes it clear it was to get back at her for mocking him.
The fact that Christian Nguyen has powers explains all of the Too Dumb to Live that the people in the Mount have had over the course of the series. For example the people who freaked out over Peezee in Ex-Heroes split into two factions the ones with the ones with Henry all backed down once Cerberus explained how illogical their actions were, while the ones with Christian all attempted to rush Gorgon.
After Death movement in Ex-Communication which was nothing short of suicidally stupid.
Hilarious in Hindsight: In Communication max said that though the box is big Karen cant think outside of it. Then in Purgatory Karen didnt really believed the insanity until her father mentioned she had been mentioning his name in her sleep plus her gut feeling made her dive full force into his story.
Barry believed his named is relatively unique later we find out that there were three B. Burkes and two Barry Burkes listed in Albuquerque.
Jerkass Woobie: For four months Christian Nguyen was trapped with her own worse nightmare
Shes upgraded to Woobie status once the reveal happens given that there is no way of know when or even if she can be freed
Christian Smith has become the punching bag of the Mount.
Nightmare Fuel: Ex-Purgatory is chock full of these thanks to what the characters perceive as being the "real world" being an illusion.
Any click of a pen and itch could be an ex-human close to you or currently eating you alive.
For that matter you might not actually exist you could be nothing more then a figment of someone elses imagination
Youre walking down the street minding your own business and suddenly your in a post apocalyptic world surrounded by zombies
Tear Jerker: Gorgon's reaction to seeing Banzai's zombified corpse.
Rewatch Bonus: Due to his penchant for Foreshadowing two even three books ahead, the series is far more entertaining the second time around.
Squick: The fate of Banzai and Jessica Alba's bodies. Fixed in the latter case.
What an Idiot!: George decides to take Madeline a.k.a Corpse Girl along to a new group of survivors despite the fact she looks like a talking Ex. She does prove to be an asset, but it was still a pretty dumb move.