The Avatar is a powerful being who has been

reincarnated over many lifetimes. It is the

Avatar's duty to master all four elements, and to

use that power to keep balance amongst the four

nations. The Avatars follow a cycle, so when an

Avatar dies the spirit is reborn the successivo nation

in the cycle: It goes Water, Earth, Fire, and

Air. There can only be one Avatar at a time. The

Avatar also possesses the ability to meditate

into the Spirit World. They are also able to

contact the spirits of precedente Avatars through

meditation and gain wisdom from them. The Avatar

can also enter what is called "the Avatar State."

In the Avatar State, the Avatar is at their most

powerful, but also their most vulnerable. The

Avatar State is signified da a glowing of the

eyes (and in Aang's case, glowing Arrow tattoos).

When in the Avatar State, an Avatar's bending

strengh is heightened and he o she can perform

very powerful moves. But if an Avatar is killed

while in the Avatar State, the Avatar cycle is

broken, and the Avatar ceases to exist.