|“||We are the protectors of the forest! We won't let you burn it down! Wipe them out!||„|
|~ Aye-Aye as a Dark Spirit to a group of Firebenders before ordering his fellows to slaughter them.|
The Dark Spirits are a malevolent sub-group of Spirits and the major antagonists of Book 2: Spirits in The Legend of Korra, first appearing in the second season of the latter show. They are Spirits corrupted from the influence of Vaatu.
The Dark Spirits are Spirits that were originally corrupted by Vaatu ten thousand years ago, who took advantage of certain Spirits anger towards humanity to make corrupting them easier.
The first known appearance of the Dark Spirits was twenty years before the events of the present day, when Tonraq destroyed a sacred forest while in pursuit of raiders. In retaliation for this sacrilege, Dark Spirits attacked the Northern Water Tribe and caused massive devastation before Unalaq was able to calm them. Following this Tonraq was banished from the Northern Water Tribe, allowing Unalaq to become chief.
The Dark Spirits returned twenty years later, first attacking Water Tribe fishing ships. Another later attacks the Southern Water Tribe itself on the night of the Glacial Spirits Festival. It proves to be a formidable opponent for Korra, Tenzin, and Tonraq, until Unalaq is able to calm it using spiritual techniques that turns it back into a peaceful Light Spirit. Following this Korra agrees to join Unalaq so as to learn how to better handle Dark Spirits in the future. Unalaq tells Korra that the first order of business is to unlock a spiritual portal and in so doing bring back the Southern Lights, which would calm the Spirits for a time.
After braving a ruined oasis filled with Dark Spirits Korra succeeded in bringing back the Southern Lights, but Unalaq cautioned that this would not be the last of the Dark Spirits and that there was still work to be done. Indeed, while fleeing from Unalaq's children Eska and Desna, Korra comes under attack from a particularly large Dark Spirit that manages to drag her underwater.
Dark Spirits later show up serving Unalaq in the Southern Water Tribe, and are used by the Northern Tribe as shock-troopers. When Korra battles the now Vaatu-possessed Unalaq for the fate of the world, a swarm of Dark Spirits try to destroy Korra's vulnerable body but are kept at bay by Korra's friends long enough for Korra to triumph over Vaatu and Unalaq, with the latter being destroyed. It is assumed that the Dark Spirits returned to their light selves without Vaatu there to corrupt them.
- Grey DeLisle, the voice actress of Azula, voiced a Spider Dark Spirit from the episode "Darkness Falls". The spider's voice is the same as Sunekura's, but digitally altered.
- Unalaq's claim that Dark Spirits are not truly evil but rather the result of imbalance is similar to Taoist beliefs regarding the ideas of light and dark and good and evil.