Since the legend of korra, ive been curious about what happened afterwards. I always thought about having two avatars, both benders of all kinds but one stronger with water and fire, the other stronger with earth and air. Plot wise i thought about showing an unused villain type. tyrant, deceiver, conqueror and revolution maniac have already been used, so i was thinking civil oppressor. Basically, bending has been reserved for the higher class, while the lower classesare forbidden. One avatar trying to change this politcally, the other one rebelliously. This would eventually drive a wedge between them until they eventually come together again. Thats all i got so far.