There isn't a single, overarching antagonist in the series, but Greg often faces challenges and conflicts with:
* His own insecurities and anxieties: Greg is a typical middle schooler, struggling with fitting in, dealing with bullies, and navigating social situations.
* His family: Greg often butts heads with his parents and brother, Rodrick, who frequently cause him embarrassment.
* School bullies: Throughout the series, Greg encounters bullies like Rowley's friend, Fregley, and other classmates who make his life difficult.
So while there isn't a single villain, Greg's internal struggles and external challenges, particularly those involving his family and classmates, contribute to the central conflicts in the *Diary of a Wimpy Kid* series.