The Kyoshi novels are worth the read if ONLY for the brilliant world building of FC Yee. Most importantly, the extended lore about the Air Nomads.

It's so beautiful and painful to read about how the Air Nomads lived and were perceived by others before the genocide. You know that famous post that said that Sozin killed the very embodiment of fun when he killed the Air Nomads? Well, it was also so much more.

Air Nomads were beloved and considered good omens in most parts of the world. A blessing from a monk or a nun was considered a rare gift by people.

No stupid rules of hierarchy and manners applied to them. People of all ranks freely approached them without any formalities, which is huge given how elaborate the traditions and manners of the other nations were (what a breath of fresh air for them, huh?)

People would stop fighting because of the mere presence of an Air Nomad, out of respect for their teachings. Sightings of sky bison were every child's dream, and the Air Nomads always passed by with cheerful waves and smiles for them.

In the original show, we know that Aang travelled a lot as a child and had friends like Bumi and Kuzon. Imagine the happiness of a small town when a bunch of giggling bald children visited. Imagine the special (vegetarian) snacks they would have prepared beforehand for them. Imagine the absolute chaos their own children would get up to with them.

Air Nomads resolved disputes. They carried messages to far off relatives for no cost. They were the link through which all of the nations communicated. They embodied fun, happiness, and hope.

this is what Sozin killed. And it may never be fully recovered, even after harmonic convergence in LOK. Something so important will be lost forever.