Kosen: Bultina's younger sister, an incredible earthbender, and a high level metalbender. She likes Hikar and tries her best to show him metalbending in their adventures, as well as dating him.
Nikumi: Hikar's animal companion, a loyal armadillo lion he adopted before he was born.
Additional Main Characters
Aria: Yurei's only daughter and only airbender, she obeys her father and, alongside her two younger brothers, forms the "Red Triangle". She's the most powerful and has an issue with Bultina.
Zeick: Aria's middle combustionbending brother, he's wild and crazy but rational at the time of important decisions like obeying his father and being part of the "Red Triangle".
Deyek: The youngest brother of the "Red Triangle", a capable bloodbender, a little bit scared of his power, but he always does what his father says in order to make good.
Iruka Sato: A forty-year-old Southern Water Tribe man, good friend and a cool waterbending teacher to both Hikar and Kensi, who helps them to also master spiritbending, and discovering Kensi's bloodbending talent.
Palmex: A young revolutionary spirit-alien that doesn't like Mars's order and governance from Roshmark, so he helps Team Avatar to defeat him.
Yurei: Hikar's former airbending instructor, he thinks the world should have a new order and reveals his real alliance.
Zhasha: Yurei's spiritbending twin sister, she thinks the same as her brother and has a special deal with Kensi and Shaila.
Hakai: An evil dark spirit that wishes to destroy all humans that interfere with the Spirit World colonizing it or getting benefits. He uses Kosen's anger as an advantage to destroy the Avatar.
Roshmark: A mysterious spirit-alien that governs Mars populated by spirit-aliens of the same kind.
Dark Hikar: The most recurring enemy, and it's inside Hikar's mind, as the result of a growing Vaatu inside Raava.
Amala Sato: Yurei's ex-wife and mother of Aria, Zeick, and Deyek. She's a wise, kind and loving firebender businesswoman.
AvatarKorra: Hikar's predecessor as the Avatar, she gives him advice on how to control the situation in the world and the Spirit World, and with Yurei's "Red Triangle".
Rohan: The last pure airbender alive, he's already 127 years old and rides a wheelchair, but he's still capable of airbending.
Asami Sato: The widowed wife of the previous Avatar and former leader of Future Industries. She's now a member of the Order of the White Lotus and discovered Hikar was the new Avatar by choosing the betrothal necklace she gave Korra in the past.
Janji: Iruka's airbending gay husband, a funny guy that is still trying to get his Air Nomad tattoos.
Li Hua:Shaila's young sister, a curvy girl that likes to help her sister and have a good relationship.
Raava: The light spirit that fused with Wan and Korra consisting their fusion in the Avatar.
Vaatu: The dark spirit that was destroyed by Korra, but it starts to recreate from inside Raava, creating a double personality in Hikar.
Zeraax: A spirit created from a clone of Raava just to create a new martian Avatar with spiritual energy.