Buttercup is the toughest fighter of the Powerpuff Girls, the short-haired tomboy in green, created by Craig McCracken and introduced alongside Blossom and Bubbles in the 1992 short Whoopass Stew: A Sticky Situation and the 1995 short Meat Fuzzy Lumkins, then as a lead from the 1998 Cartoon Network series. E. G. Daily voiced her in the original run; Natalie Palamides took the role in the 2016 reboot. In The Powerpuff Girls Movie, Professor Utonium names her Buttercup only because the name starts with B like her sisters, and she answers with a crossed-arm “Hmph,” a beat the film treats as the start of her stubborn streak. The same movie makes her the sister who throws the first real punch, flooring the bully Rocko Socko and accidentally showing the others that their powers can stop crime.
She is headstrong, easily enraged, and the sister most likely to skip the plan and hit something. That aggression is also a flaw the series keeps returning to. In Cover Up she depends on a worn green blanket for confidence and is humiliated when the town finds out. In Moral Decay she knocks out teeth for the tooth-fairy money and has to face what she has been doing. Makes Zen to Me pushes her to get her temper under control. She bullies classmates, mocks Bubbles, and picks fights with Blossom over leadership, then turns fiercely protective the moment either sister is actually in danger. Her color is green, her temper is the point, and the show is careful to show that the mean streak sits next to loyalty rather than replacing it.
Later versions keep the scowl and the fists. Powerpuff Girls Z and the 2016 reboot both preserve her as the spice of the recipe, the one who would rather fight than talk and who resents anything that feels girly, including the kiss required to defeat the Rowdyruff Boys. Developments across the franchise rarely soften her into a different character. They instead put the recklessness on trial, give her a reason to apologize, and send her back into the fight as the sister who still wants to be the one throwing the last punch.