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.
Colton Banes, also from Nightrise, is an assassin for Nightrise hired to track down Jamie and Scott, two of "The Five". When Jamie escapes Colton kills "Uncle Don", the stage manager they were staying, and his wife to pin the rap on Jamie. When he and his partner Kyle Hovey report back to Susan Mortlake, she has Colton strangle Kyle. Colton does this immediately and without remorse, stating the he always hated Kyle. When Jamie tries to scan him to find Scott's location, he sees not only the after mentioned crimes, but also sees memories of a girl locked in a battered trailer with puncture wounds. When Jamie tries to go to prison under an alias, he is caught and one the guards reports him to Colton. Colton tells the guard to turn off the Air Conditioning in the cell, which the guard does reluctantly. During the raid on the prison Colton shoots Jamie in the back.
The fifth and final book Oblivion gives us the new chairman of Nightrise. The chairman is introduced by holding a press conference with ten thousand members of Nightrise, and says that they will be taken away to have their limbs cut off and replaced with weapons for the battle with the five. When one member refuses, the chairman has him shot dead before sending guards in to beat everyone up and take them away by force. The chairman orders his second-in-command, Jonas Mortlake (Susanís son), to make Scott do a Face-Heel Turn so that without him, the five will never be united, telling Jonas that if he fails, he will suffer the same fate as the other members of Nightrise. When Matt and Richard are captured, the chairman has Matt crucified and tortured by having his skin flayed and his bones broken. The chairman tries to kill Richard in front of Matt, stating that Matt will be forced to watch his best friend die, and will than continue to be tortured forever.
Everyone Is Jesus in Purgatory: Matt's story is suspiciously similar to the life of Jesus Christ. Born with special powers according to some higher plan, destined to save the world from The Legions of Hell and their very Satan-like leader, leads a small group of followers of whom the closest to him is named Pedro ('Peter' in Spanish), accepts his destiny despite wishing there was another way, betrayed by one of his companions, flogged and beaten and hung up to be jeered at, died, came back and ascended to Heaven right in front of his friends.
Magnificent Bastard: The world's magnificent bastards are working for the Nexus: Shang Tsung, a ruthless Asian crime lord, a DGSE spy and a not-so-subtle Rupert Murdoch analogue, are both the villains of another story, but here are vital warriors on the side of good.
Stoic Woobie: Matt again, by the last book. Also Pedro, who never really complains despite being a starving street urchin who spends most of his pagetime being hunted, abused, betrayed, nearly killed on several occasions and repeatedly exhausting himself trying to use his power on grievously-injured people who often don't make it anyway.
Uncanny Valley: Shape changers pretending to be humans have this effect. Of the few that are mentioned, not a single one has maintained their deception for any length of time: One lets his disguise slip when he meets Scarlett, the other has a freakishly round head, one can't speak, one doesn't notice cutting his own thumb off, and one doesn't notice an enormous insect crawling over his eye. The best impersonation so far has been "Audrey Cheng", and even it gave the game away when it forgot to eat. Scarlett rumbled it when she realized the only time she had ever seen "her" express hunger was looking at a fishmonger's slab.
Horowitz never says which party is which, only that the guy under the control of the Old Ones (Baker) is the nominee of one of the major parties and Trelawney is the other's. It could be interpreted either way: the environmental and social justice stuff make the Old Ones sound Republican, while from a religious perspective they're more likely to be backing the Democrat. However, several hints do favor this interpretation, most notably that the anti-Old-One candidate, thinking the security he's surrounded by, notes that only one crazy person with a gun is enough to make it necessary, that it is very easy to get a gun, and he might want to change this. That's a much more likely set of thoughts for a Democrat than a Republican.