A man is tortured on live TV in Man vs. Beast. Three Military women show willingness to torture a 16 year old in The General but don’t get the chance to get to extreme.
Lauren’s Father hits her in the Recruit but is later arrested for this. Fahim’s father in The Sleepwalker beats and kills his wife, beats his own son, and used him as a hostage in a stand off with Police. In the same book, another man beats his girlfriend and gives her a black eye, then uses her as bait to start a fight with James.
James’ mother at the start of the The Recruit. Everyone at Cherub is either an orphan or was abandoned as a kid. A kid’s father and older sister is killed in Divine Madness, although both were villains. Fahim’s mother is killer by her husband in The Sleepwalker, and his father is later shot dead in a gun battle with police.
Some books, most notably The Sleepwalker and Divine Madness have bittersweet endings, but not an outright bad or unhappy ending. Some groups or criminals remain at large after some missions and never face justice.
A character is called a W*g at the start of Maximum Security. Several instances of F****t and Q**R throughout earlier books. Several uses of R*****d throughout the series. Nicole is bigoted towards the elderly and throws a cup full of spit in an Elderly Man’s face in Class A.