The negative form of the underlined sentence is

Gregory “Greg” Heffley is an American middle school student and also the main protagonist of the book series Diary of a Wimpy Kid.

Greg is lazy, petty, slightly narcissistic, sociopathic, egotistical, eccentric, egocentric, usually backstabbing, and sometimes even selfish and dishonest, and apparently lacks talent. He hardly has any skills aside from video games and possibly singing. However, despite all this, Greg has had his kind and caring moments, but not that often.

Adapted from https://diary-of-a-wimpy-kid.fandom.com/wiki/Greg_Heffley