Aang may have run away to escape the duties demanded of the Avatar, but his inevitable (and belated) return heralds hope for a world oppressed by the violence of the Fire Nation. As the most important human being in the world, Aang is blessed with limitless power, but is simultaneously limited by his message of peace and fraternity — in that he can't let loose whenever he pleases.
A lot of people have met him over the course of his life, but how many of them can confidently say that they know everything there is to know about the Avatar? In fact, there are still several things about Aang that remain unexplained, both in the series and in the extended canon of the franchise.
10 Where Did He Come From?
Aang was born around 12 years before Sozin's Comet, but the identity of his parents has never been revealed. This is because newborn Air Nomads are adopted into the culture (mostly because the parents follow the traditional philosophy of detachment from earthly things.)
In the end, it doesn't matter where Aang comes from because every Air Monk behaves as a provisional parent for all the kids that live in a particular temple.
9 Why Did He Stay Frozen For A Century?
Once Aang's Avatar State is provoked by the climatic threat to his life, it seals him and Appa within an enormous spheroid of ice. One would assume that this "cryogenic" state would be suspended once the storm passes, but this is obviously not the case.
However, Katara succeeds in (accidentally) waterbending him out, a feat that even the Avatar State is inexplicably incapable of. Is this because Aang is not connected to his past lives while frozen, and therefore cannot use their powers to come out? Or because defeating Ozai has always been his destiny?
8 How Did He Become An Airbending Master?
As the Avatar, Aang is far superior to most of his peers, even those considerably older than himself); and before he turns 10, he surpasses his own instructors.
However, to become an airbending master, it is expected that the practitioner can perform each of the 36 levels. Aang can only manage 35, but because of his development of the unique air scooter, he is allowed to receive his tattoos. What are these levels? How complicated are they?
7 What Is The Height Of His Power?
Forget the Avatar State; the most incredible aspect of Aang's powers is that of energybending, with which he can literally extract "bending" itself from anyone he chooses. He applies this technique to both Ozai and Yakone, and is successful each time.
But this can't possibly be the only amazing thing Aang can do. Is he strong enough to pull the sea floor out of the ocean like Avatar Kyoshi? Is he skilled enough to cause four simultaneous volcanic explosions like Avatar Szeto?
6 How Did He Learn Energybending?
The Lion Turtle, a relic from the ancient past, whispers the secrets of Energybending to Aang, conveniently allowing him to protect his pacifist oath and put an end to the Fire Lord's tyranny.
However, the form requires that his own life force be "unbendable," which supposedly means that nobody can energybend the Avatar. And yet, Korra is forced to experience this miserable fate under Amon, which makes no sense. So the question is: what exactly are the instructions given by the Lion Turtle?
5 What Did He Do After The Hundred Year War?
Team Avatar brings back balance to the world — the Earth King is reestablished on his throne, Zuko is crowned the Fire Lord, and the two Water Tribes finally recover from some serious war damage. Aang is responsible for the germination of the United Republic, a new country for those left homeless and rootless when various national borders shift back into place.
He also assists Zuko in discovering his mother, as well as Toph in the battle against General Old Iron. Nevertheless, there is no information about most of Aang's activities as an adult, except for a few sepia scenes that play out in Korra's memory.
4 How Exactly Did Ozai Fix His Chakra Alignment?
The combination of Aang's incomplete knowledge about his final chakra and Azula's violent lightning bending attack permanently prevents him from eliciting the Avatar State.
It is only during his battle with Ozai that he is tossed into a pointy rock formation in such a way that a small protrusion fits inside his wound hole like the perfect jigsaw piece. Why would something this simple open the seventh chakra? Shouldn't Aang have let go of Katara before this could happen? Does this mean that Guru Pathik only spouts nonsense?
3 Why Couldn't He Learn Metalbending?
Interestingly, Aang wishes he could be a metalbender long before the style is even invented, but he is simply unable to turn his dreams into reality when Toph attempts to convey her newfound knowledge.
This just doesn't compute, because the Avatar is technically supposed to be the most powerful bender in any single element after defeating the respective masters. What's stranger is that Aang can employ Toph's seismic sense technique, which is essentially all that is needed for metalbending.
2 How Did Aang Die?
Aang's death at the age of 66 is completely unexpected, because Avatars generally live for a century or two. The reason behind this is assumed to be the fact that his century-long suspended animation had aged him considerably (in a spiritual sense).
Does he die peacefully in his sleep, though? Is it a disease that kills him? Is the process painless? There are too many loose threads with respect to Aang's death. Also, why does he look younger than 66 when he premieres in Korra's visions?
1 What Happened To Appa & Momo?
Appa and Momo do not appear in the sequel series, nor are they referenced in detail (Momo is not even mentioned once). It makes sense that the Sky Bison would have died at the same time as the Avatar, what with their spiritual link and all.
Do they cuddle together one last time before drifting away into the void? Why does Aang not come with Appa to see Korra like Roku does with his dragon? And most importantly, when, how, and why did Momo die?