We don't see the events of First Night directly, but all the allusions to it paint a truly nightmarish picture: chaos, bloodshed, cars breaking down in the middle of the highway leaving people trapped as the zombies close in, nukes falling. Which led to radioactive zombies, as if regular zombies weren't bad enough, who were so radioactive they could kill people without even touching them.
Bear in mind, this is before people realised the only way to kill zombies was by stabbing them through the back of the neck or chopping off their heads. Which meant no matter how much they shot at, set fire to or even dropped bombs on the zoms, they kept coming back...
Rot & Ruin
We see the true extent of Charlie and the Hammer's sadistic cruelty about half-way through the book. They torture Rob Sachetto to death and then lead his zombie to the Imura house so he can murder Tom and Benny. Then they hold Morgie, a literal child, at gunpoint, and force him to watch as they terrorise the Rileys. Eventually, they kidnap Nix, beat Jessie to death, and leave Morgie to bleed out from a massive head wound outside the house.
Nix's account of that night makes it even worse. When Jessie tried to fight back, Charlie lost his temper and went after her 'like an animal'. When he was finished beating her to death and trashing her house, he left her on the bed 'as a present for Tom'.
