Along with Bubbles and Buttercup, she was first created by Professor Utonium with sugar, spice, everything nice and Chemical X. She serves as one of the main protagonists in the show along with her sisters.
She is the self-proclaimed leader of the Powerpuff Girls, and appears to be more intelligent then her sisters. She is very orderly, having all of her things in a specialized place. According to the episode Run, Blossom, Run, she has perfect kindergarten attendance and was temporarily accepted into a top university, to which she gained a paranoia to being late in that she sometimes got up early even on weekends.
She usually exaggerates and sometimes speaks in a naggy or even condescending nature. She is also very analytical coming up with most of their plans, but still is protective and cares for the well being of her sisters and others. She is also very studious, as she is drawn to intellect-enchanting toys and has often been seen sitting and reading a book. Another sign that she is studious is that in the episode Power Noia, she has a nightmare about failing a test she forgot to study for.