David and Tamani meet for the first time. It's not as awkward as it could be, and Tamani has David drive him to Barnes's house; they talk on the way.
Tamani explains trolls as a glitch in evolution: not quite human, very strong, but misshapen, cruel, and stupid. They lack symmetry, which can make them still look like people but very ugly, or it can make them total freaks of nature with odd numbers of limbs and stuff like that.
Also, trolls don't do well with sunlight, but modern inventions like sunscreen have helped them move about in the human world, where some of them even have some influence.
Barnes could've recognized Laurel as a faerie, since trolls can pick up on the smell of blood or its absence, but each time they ran into each other, there was something else to mask Laurel's lack-of-human-blood-smell (such as David reeking of bonfire smoke at the house, the clinical stench of the hospital, or the fact that David had bled on Laurel a little when the trolls captured them). So basically, Laurel's gotten lucky.
Laurel asks to come with Tamani into the house, and he refuses until she promises to leave at the first sign of trouble. David stays behind to man the getaway car.