Please take a look at this proposed tree of organisation and comment
*Agatha Christie Characters
**Recurrent characters
**Hercule Poirot characters
***ABC Murders characters
***Death in the Clouds characters
***etc
**Miss Marple characters
***The Body in the Library characters
***Murder in the Vicarage characters
*Etc
*Etc
*Characters not created by Agatha Christie
**Characters by other authors
**Characters from adaptations of Agatha Christie stories
***Les Petits Meurtres d'Agatha characters
****Le cheval pale characters