When Does Aang Possess The Avatar State Fully?

I still get chills thinking about the different times Aang gets swallowed by the Avatar State because they mean very different things emotionally. As a fan who re-watches scenes when I’m stressed, I notice that the State takes him over most powerfully in the final battle during 'Sozin's Comet'—that’s when the past Avatars show up like a chorus and he radiates pure, terrifying bending energy. Earlier big moments, such as in 'The Siege of the North' and the episodes around 'The Avatar State' and 'The Crossroads of Destiny', show it popping out when he’s scared or hurt.

But if you mean "fully possess" as in "Aang being in complete control of the Avatar State," then the journey is more subtle. 'The Guru' sets up the spiritual path—opening chakras, facing attachment—but he never finishes that perfectly because of interruptions and trauma. The decisive moment is actually when he learns energybending from the lion turtle in the comet arc; instead of letting the Avatar State turn him into a killer, he uses a new technique and sticks to his values. So the full package—power plus conscious control and moral choice—lands in the Sozin finale and the scenes right after it. It’s one of those rare endings that balance spectacle with character growth, and I always feel a little proud watching it.

I like to think of Aang’s relationship with the Avatar State as two milestones instead of one straight line. The first milestone—where the State completely takes over and he displays the faces of past Avatars—happens most dramatically in the 'Sozin's Comet' finale (with earlier major displays in 'The Siege of the North' and episodes around 'The Avatar State' and 'The Crossroads of Destiny'). The second milestone is about control and moral agency: he nearly masters it in 'The Guru' but is interrupted, and he truly proves his command when the lion turtle teaches him energybending during the comet arc. That allows him to use Avatar-level power while staying himself, which to me is the real "fully possessing" moment—power plus choice. It’s less flashy on screen than the glowing faces, but it’s the one that matters long-term.

The way I see it, there are two different ways to interpret "when Aang possesses the Avatar State fully," and I like to separate them: one is when the Avatar State physically overwhelms him (Aang is possessed by the power and faces of past Avatars), and the other is when Aang actually masters that state and can call it without losing himself. Those are related but not the same, and the show teases both arcs across Book Two and Book Three.

If you’re asking when the Avatar State takes over him in its most complete visual/powerful form, the biggest moment is during the finale of 'Sozin's Comet' — that scene where the past Avatars appear behind him and he explodes with raw bending is the clearest example of a full Avatar-state possession display. Earlier big showings happen in 'The Siege of the North' and in bits across Book Two (the episode 'The Avatar State' and the clash in 'The Crossroads of Destiny'), but those are more fragmentary or triggered by trauma. If, instead, you mean when Aang finally has real control—when he can decide how to use that power without being consumed—that arc is trickier. He almost reaches emotional mastery in 'The Guru' when Pathik helps him open chakras, but Azula interrupts. The real turning point is the lion turtle scene during the 'Sozin's Comet' run: he learns 'energybending' and makes a conscious moral choice to remove Ozai's bending rather than kill him. That choice is the clearest sign of matured control: he can access Avatar-level power and still remain himself.

So, the short-but-nuanced takeaway I keep coming back to: full possession (faces and raw force) visibly occurs in the 'Sozin's Comet' climax, but true personal mastery and ethical agency over the Avatar State is completed only once he integrates his spirituality and the lion turtle’s lesson — he never becomes a permanent Avatar-State automaton, he becomes a responsible Avatar instead.