The world of “ Avatar: The Last Airbender ” is expanding with a new fighting video game and animated YouTube series, it was announced at New York Comic Con on Sunday. The beloved Nickelodeon animated series celebrated its 20th anniversary at New York Comic Con with a panel that featured original cast members Zach Tyler Eisen (Aang), Jack De Sena (Sokka), Michaela Jill Murphy (Toph), Dante Basco (Zuko), Mae Whitman (Katara), co-creator Bryan Konietzko and moderator Janet Varney (Korra).