Because of his half-fae heritage he is sometimes referred to as a 'Goblin' or 'Goblin-boy' by Peter and other members of the Demi-monde. Zach is the first character to use the nickname 'The Isaacs' when referring to Peter, Nightingale, and the Folly. 
Peter Grant first encountered him during Operation Matchbox, the investigation into the murder of American-exchange student James Gallagher. Zach was the housemate and local guide to James Gallagher prior to the events in Whispers Under Ground.
Relationship with the Quiet People Edit
Zach unofficially acted as a go-between between some young members of the Quiet People and the Demi-Monde prior to Whispers Under Ground. He is friends with Stephen and had an unrequited love for Elizabeth.
He later becomes the semi-official liaison between the Quiet People and Transport for London negotiating their assistance in the Crossrail project. Zachary also helps integrate the Quiet People into above-ground society by taking them on pub crawls and introducing them to the last 50 years of pop music. He is helping Elizabeth establish an above ground nursery to acclimate Quiet People children to direct sunlight.
Relationship with the Folly Edit
Zach displays a skeptical attitude toward the Folly as a justice and peace-keeping organization. During Whispers Under Ground he infers that the 'Isaacs' and the 'Law [police]' are not necessarily the same thing.
During Operation Matchbox he was very reluctant to provide information on the Quiet People and James Gallagher. He misled Peter Grant's investigation into the murder weapon and Empire Pottery multiple times. He also attempted to obscure his ability to locate the Goblin Market from Inspector Nightingale, but was unable to do so by the laws of Obligation.
- A girl who lives on a boat in Little Venice and who grows weed (or cocaine) underwater.
- As a child he saw a unicorn in Epping Forest.
- A shebeen on top of a council flat with bootleg comedy.
- His Grandad knew Arthur Conan Doyle.
Lesley May Edit
Zach approached Lesley May romantically shortly after meeting her at the Folly. They began their sexual relationship during or before the events in Broken Homes. He may also have unintentionally helped her set up her initial contact with the Faceless Man around this time. Their sexual relationship continued after Lesley joined forces with the Faceless Man, and he has refused to assist Peter in locating her.