Atencio was an individual of unknown gender.
According to a story once told by the Ghost Host, a book by Atencio was among the volumes in the bookcase in architects Mr Davis and Mr Coats's study as they got to work designing Gracey Manor. It was filed next to a book by Crump.
Behind the scenes
Atencio's name appears in the 2005 story Blueprint for Murder. Like all the names of authors in the story, it is an allusion to one of the Imagineers responsible for designing The Haunted Mansion in the real world — in this case, X. Atencio.