Numberjacks
The Numberjacks are the heroes.  Each of the numbers 0-9 is an individual character and each is broadly the age of his or her number. 0, 2, 4, 6, and 8 are male, while 1, 3, 5, 7, and 9 are female.  However, the gender of the individual Numberjacks is never explicitly stated. The males and females are in a pattern.