The Legend of Korra

Beginnings (1) (2x7)

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In order to cleanse herself from a dark spirit's attack, Korra must reconnect with her Avatar Spirit by finding Raava. To do so, she needs to learn about the origins of the first Avatar, Wan. He tells her how he received the power of fire and learned the ways of the spirits, as well as how he was the one responsible for unleashing Vaatu, the spirit of darkness, into the world.