Cleo lives with her father, Ramses de Nile and her older sister, Nefera de Nile. Ramses de Nile is a antique dealer. Ramses wants Cleo to follow in his foot steps. Nothing is known about Cleo's and Nefera's mum. In The Ghoul Next Door, Nefertiti is said to be the girls' aunt.
The first time Nefera is mentioned is in the webisode "Miss Infearmation". Nefera is a model and was a previous fear squad leader. In the School's Out diaries and webisodes, Cleo and Nefera don't seem to get along well.
Cleo de Nile has a pet snake called Hissette. Her attitude reflects Cleo's. In the Monster High books, Deuce gave Hissette to Cleo as a gift. In Cleo's diary, it was stated that Hissette was given to her as a gift from Egypt. In the books, Cleo also has seven cats named: Chisisi, Bastet, Akins, Ebonee, Ufa, Usi, and Miu-Miu. This is a reference to how cats are worshipped by people (especially royalty) in Ancient Egypt.
Cleo is in a relationship with Deuce Gorgon. She previously used to date Clawdeen Wolf's older brother Clawd, but according to Ghoulia it ended badly. Cleo started dating Deuce the day after they broke up. The only reason why Clawd and Cleo dated was because of C.a Cupid's love arrows. It is stated that in C.a Cupid's diary that Cleo and Deuce started dating on the 1st November.
- Release: July 2010
Cleo wears a strapless jumpsuit made up of light gold coloured mummy wrappings. On top, she wears a tight turquoise wrap around top with black lining. She carries her phone on a gold strap on her thigh.
Dawn of the DanceEdit
- Release: September 2010
Cleo wears a blue-green coloured dress with gold heels. Her hair is cut short and her makeup is dramatic.