As you could tell by the name, the Ninja's kids (the main starting ones for now also if I decide to add more later on). The list includes the twins, by boy, girl and parents.

Nick and Jackie (Jay and Nya)

Sky and Kaylie (Kai and Skylor)

Zack and PIXIE (Zane and PIXAL)

Cameron and Sally (Cole and Seliel)

Eris and Lilly (Lloyd and Harumi (OR) Chamille)