So I posted this thought a few hours ago:
And it seems to have caught on rather quickly! Which is amazing!
But I have something to add to that (Because ultimately I’m trying to set up a plot for a fanfiction)
So Roku was taken away from the Fire Nation and he traveled around the world and was taught about the Avatar’s virtues. Aang was an airbender who already had learned many virtues but was still taught the extras that come with being the Avatar.
Korra was condemned to the Southern Water Tribe but the sages still taught her about the importance of her protecting the world.
This is the age-old nurture vs nature discussion but what if that’s a key aspect to this:
What if somebody raises the next Avatar to be evil? What if the Avatar never grows up learning the virtues and responsibilities and instead grows up learning vengeance and rage? That mixed with the nature that perhaps the person who is the Avatar is just … well not nice. I don’t want to give too much away because I think that I’m actually starting to develop a plot here but does that sound plausible?