Nico

Nico is an infant Demon who is the daughter of Beelzebub III and sister of Beelzebub IV

Appearance
Nico, despite being several years younger than Beel is the same exact size. Her hair is kept in to ponytails at either side of her head, Her pupils and iris are larger than his and she has a pacifier the same as her brother.

Unlike Beel she wears clothing. A small top with a picture of a teddy bear on the back and a pair of pants.

Nico is a bit similar to Hajime Kanzaki's niece, Futaba Kanzaki before 2 years later.

Plot
They wanted Oga to look after her too.