Luan

Spoilers for The Legend of Genji 'ahead. Read at your own risk.'

Luan is the fake avatar. Global unrest, panic, and looming war had some people create a fake Avatar, which is Luan.

Born in the southern city of Gaoling, Luan was named Korra’s successor as the new Avatar by the White Lotus and Dai Li at a young age. His family moved to the upper ring of Ba Sing Se, and Luan received an elite education along with world-class earthbending training. A personal favorite of President Bao Jun and the darling of the Earth Federation, Luan has developed the charisma, intelligence, and physical prowess necessary to become a great Avatar. Despite mastering earthbending and metalbending, Luan has not yet successfully firebent. As he gets older, he begins to question his skills and whether or not he’s truly prepared to take on the role as Avatar.

Early Life
Luan was announced as the Avatar at 6 years old. He and his parents, Cheng Li and Mingyu, moved to the inner circle of Ba Sing Se for protection. As he gets older, Luan is frustrated with the slow progress of learning earthbending. At 16, Luan begs President Bao Jun to learn metalbending, so he allows it. He and his animal guide, Yin Cheng, moves to Zaofu to learn metalbending with the Beifongs.

Trivia

 * Luan is the second known individual, mistakenly believed to be the avatar. The first is Yun.
 * Curiously they are both earthbender, and were believed to be successors of a young dead avatar, belonging to the Water Tribe.