Obviously, human spirits can reincarnate, as the Avatar is constantly reincarnated into another body.
Through Avatar: The Last Airbender and Avatar: The Legend of Korra, we see and hear about spirits of people which are trapped in the spirit world. Do any human spirits other than the Avatar ever get reincarnated into a new body?
There seems to be very little specific information regarding this, in the canon.
However, there is one clue which makes me think that all humans do have multiple lifetimes: when Raava is speaking to Wan as he lays dying on the battlefield, she tells him "we will be together for all of your lifetimes."
It's a subtle thing, and definitely open to interpretation, but my reading of that line (the text and the delivery) is that "all of your lifetimes" isn't a surprising concept. Wan doesn't react with surprise to the thought of being reincarnated, and Raava just throws it out there with no preamble. It isn't "Don't worry, I will allow you to live again" or "Yours is a story that will cross many lifetimes." The multiple lifetimes bit is just assumed, the important thing is that they will be together through all of them.
It's hardly conclusive, but given that bit of evidence I'd say the scales are tipped toward all people having multiple lifetimes in the Avatar universe.
There is no certain knowledge about it, according to the first series to last one (korra).
But this is seems how is it works; Actually there is no reincarnation, there are just some sprits, and when a human's sprit bounded with a sprit from sprits world, actually the one from the sprit world caryying the knowledge and experiences and making a bridge/connection between these sprits and just passes to other nation.
You see when the bridge collapsed(unbounding raava from korra's sprit and destruction of her), all connection to past lives disappeared.
Based on uncle iroh, we may say when you die, your sprit is going back to sprit world or the other explanation when you were in sprit world if your body dies, you stuck in the sprit world. Like aiwei or commander zhao.
As conclusion, seems there is no sign of reincarnation. This is just assumed as reincarnation.
In ATLA, the Avatar was a proper or standard reincarnation, past lives of the same human spirit. Very Buddhist I'm nature. The air nomads were proper monks and strived for oneness, moving beyond the reincarnation cycle into nirvana. When the previous Air Avatar told Aang that this is impossible for air avatars, he got mad. Denied nirvana and all.
Then the fire nation, er, I mean LOL came around and changed this. It is no longer a person spirit reincarnating. The addition of Raava being the never dying spirit of the Avatar, makes the human spirits less likely to be reincarnations. They are bound by Raava like dogs on a leash. Raava never dies, and as such doesn't reincarnate. No other spirits are shown reincarnate. In fact Vatu infested spirits are shown to be killed and referred to as dying, not moving on.
I think that the Avatar series follows the idea of reincarnation. As stated above, I feel there are slight references to it being true with nobody really stating it outright. I have a personal head canon that follows the idea. Basically, all "mortal" creatures were once part of the spirit world before separating off and becoming mortal by taking physical forms. They essentially either reincarnate, or are travel to the spirit world after enlightenment. While there is no solid evidence to back that theory up, there was a quote in the video game claiming that everything was one, which implies that both the material and the spirit world are part of the same universe. I like to think of it like spirited away personally.
There is not a real reincarnation. becouse it is not only Iroh but Iroh told in a flashback that he will se his beloved son again. This means that Luten didn't reincarnate. on the end of the world people will go to heaven or hell. This becouse the man in the comic was talking about heaven. And there was not a real reincarnation becouse Avatar Wan's conection was the last who was destroyedd . this means that it is only Raava who copied the lives of the Avatars and jump from the one to the other. and yes spirits can die. But souls will never die. Humans have souls just like spirits have souls. some people are saying Raava vs Vaatu is Gos vs Saatan but that is bull shit. becouse it is Archangel Gabriel vs Lucifer Satan. Becouse the light of faith vs the darkness of ignorance. It is Balance of the truth vs the Chaos of the lies. Becouse Raava brings you to the Good and vaatu brings you to the bad. And only God can change you to Good or Bad. Raava and vaatu are guide lines. Just like Gabriel was be every prophet is Raava be every Avatar. Vaatu will come soon again. becouse people are faithless and there after many wars. This means the negative energy allows Vaatu to come back again. in only 100 Years ore sooner. I swear becouse Korra had the vision of Vaatu. There is only Raava who jumps from the one to the other
I believe that all spirits reincarnate in the Avatar world except obviously those stuck in the spirit world(at least until released). But only the avatar has the ability to remember his/her past lives.
