The release date for the fourth season of 'The Legend of Korra' is nearing, and it seems like Nickelodeon wants to increase the excitement and anticipation for the show by releasing the official trailer for Book 4.

"There would be no air nation without Avatar Korra. She opened the portals and somehow the world began anew for us. She was even willing to lay down her own life in order to protect ours," the video introduction says.

Expected to be filled with action, twists and turns, the upcoming season is set to pick up three years after the conclusion of the third season.

Fans of the show are also excited for the impending return of 'Avatar: The Last Airbender' hero, Aang.

Rumors say that in 'The Legend of Korra' Season 4, one of the major villains will be Captain Kuvira, who was introduced during the third season, and will be voiced by Zelda Williams. Fans of the metalbender character are delighted by the speculation, since Kuvira is said to be suited for a key role in the upcoming season.

However, there are also rumors that say Hiroshi Sato, a nonbending leader that designs weapons to wage war against the benders, will be returning for the fourth season of 'The Legend of Korra'.

This rumor was somehow confirmed by 'Lost' actor Daniel Dae Kim, who voices Sato.

In the said website, a fan asked Kim whether his character would have a significant role in the upcoming season, and Kim replied "I can tell you he'll be back. Shh!."

The upcoming season is going to be the last for the popular spin-off series, but fans can look back to the three previous seasons via Nickelodeon's website.

'The Legend of Korra Book 4: Balance' premieres on Oct. 3 through Nick.com and the Nick App, which is available on Android, iOS and Windows.