These books are the adventures of Edwin Drood, AKA Shaman Bond (his field name; it is a parody of James Bond's name) and he is a part of the Droods, an ancient family that purportedly watches over the world and protects it from various threats, including supernatural and magical ones.
Each Drood is entrusted with a golden (and, for some time, silver) torc, which bestows a certain "living armour" upon the wearer, giving them nearly unlimited strength, speed, durability and stealth, which can be called up or dispelled at will.
The torc also grants the wearer the Sight, allowing him to see through most magical and scientific disguises, translates any language, prevents the user from appearing in any kind of photography, videotaping, or tracking of any kind (including tracking by other Droods), prevents the user's soul from being taken away (by daemons or other creatures of the sort), and a whole host of other abilities.
Edwin (he is usually referred to as "Eddie") is a field agent of the Droods who operates in the London area.
During his early childhood in the Hall, the Droods' base of operations, Eddie came to hate the family due to its strict discipline and the lack of freedom given to him.