Kati Farkas is one of the mean girls in Gossip Girl and becomes friends with Blair along with Isabel Coates after Serena leaves for boarding school. She soon becomes Blair's loyal sidekick, or minion. First introduced in the pilot of Gossip Girl, Kati Farkas and her best friend Isabel Coates were part of Blair Waldorf's entourage. She's almost never seen without Isabel in matching outfits. Both girls often appear in the main characters's dreamscapes and remain Blair's loyal sidekicks until the latter's brief loss of status.
Kati's brother owns the apartment that would be the setting place for Blair's Japanese-themed seventeenth birthday, which led to Blair and Chuck's continuing secret relationship during the first season. Her parents move her back to Israel after spring break. In the following seasons, Kati is not present (due to Zhang attending university), but she returns in a few episodes in season 4 and 5 to compete with other minions to become Blair's bridesmaid along with Jessica Leitenberg and Penelope Shafai.
In Season 6, she is re-acquainted with Nelly Yuki, as she is writing an article on Blair's fashion line for Women's Wear Daily. Blair enlists the help of Kati and Jessica to make a good impression on Nelly, and steal Poppy Lifton's dresses, as they use the same design as her own.