Both animated Avatar adaptions have established a variety of dominant and evil spirits who live within the Spirit Realm.

He first appears in Avatar: The Legend of Korra, Book Two: Spirits, Episode 7 ... hardships and battles brought upon by Vaatu ...

23. Book 2, Episode 14: “Light in the Dark” The shonen fight between a projection of Korra’s spirit and Unalaq’s evil Avatar is controversial, but also a beautiful representation of Korra ...

Above all else Korra proves that evil — much like good ... the form of Unalaq and his quest to open the Spirit World and become the Dark Avatar. Unalaq was followed by the most haunting ...

Though this mostly was used as an excuse by the character of Unalaq in order to trick the Avatar into bringing back an ancient evil spirit, Korra argues that the world had indeed strayed away from ...

Much like seen with The Legend of Korra, Avatar ... it even stems from the fact that the human and spirit worlds are now fully merged. This new Avatar is now going to be in a reality years ...