DeeDee is Dexter's extremely ditzy, simple-minded, 11-year-old sister. She loves ballet, dolls, ponies, unicorns, messing around in Dexter's laboratory, and generally depicts all the stereotypes concerning young girls

Mandark
Dexter's arch-nemesis. Approximately equal in intelligence to Dexter, he too possesses his own laboratory, which has a very red-and-black color scheme and may be organic-based

Mom
Dexter and Dee Dee's red-haired bottom-heavy mother; a mysophobe who has trouble being around the rest of the family without her rubber gloves.

Dad
Dexter and Dee Dee's blond-haired father is the stereotypical husband and head of the household, falling directly above his wife in authority.