Ghost
A ghost is the spirit of a deceased, who become attached to the vestigium of a certain area and can live off vestigia or magic.[1]
Revenant
An avenging spirit or ghost who returns from the dead for revenge. A “ghost vampire” who lives off the magical force of others.[2]
Troll
Trolls usually want to live on riverbanks, preferably on places overshadowed by stone or brick.[3] For instance Nathaniel, a troll who acts as a police informant, lives under the arches of Richmond Bridge, having moved there from Hungerford Bridge.[4]
Vampire
They are anti-life, or Tactus disvitae. Vampires feed off the magic potential, including the vestigia, of their surroundings and of living creatures.[5]
Jazz vampire
As other vampires, jazz vampires live off energy. In this case the energy comes from jazz musicians.[6]
Genius loci
A Genius loci is the spirit of a certain place.[7]
River Spirit
Genius loci of a river.[8]
Canal Spirit
These differ from River Spirits according to Tyburn and Fleet.[9]
Leshy
He of the Forest. Genius loci of a forest.[10]
Fae
A fae is a collective term, almost like foreigner or barbarian.[11]
Unicorn
Zachary Palmer claimed to have seen a unicorn in Epping Forest once, as a child. Peter Grant was not sure if it was true or not.[12] Nicole Lacey had an invisible friend, Princess Luna, who was some kind of unicorn.[13]
Wood nymph
In the park surrounding Skygarden Tower lived a wood nymph called Sky. She died when the trees were cut down.[14]
Possibly magical creatures
Fox
Several encounters with foxes or foxlike creatures hint that foxes somehow are connected with the Demi-monde.
Mermaid
When Peter Grant first encountered a Genius loci, he asked Nightingale if it was a mermaid. His response: "That wasn't a mermaid", made Peter say: "So there are such things as mermaids". To this Nightingale only answered: "Focus, Peter, one thing at a time".[15]