Before their adventures in Equestria, Raiden visited a realm where human had the ability to control the four elements. Each land representing the element they controlled, Air, Water, Earth, and Fire. When he visited the land... he met its protector... the Avatar. He not only wished to visit his realm, but to warn him of a dire threat... the Jinsei of their realm was unprotected, and will need protection in the future. By Avatar Aang's next incarnation, Korra. But she cannot face a certain mad god alone... Raiden and Princess Celestia sent their best warriors to aid her in her struggles to become the new Avatar.