
Thanks to the long-awaited appearance of the wise Lion Turtle (the ultimate animal hybrid, whose existence was hinted throughout the series), Aang learns that he doesn't have to kill his enemy when a more righteous solution is available: Taking away the power that Ozai used to justify his imperialist slaughter. But only at the end, when he has mastered all four elements, does Aang think about what it would actually mean to "defeat" the Firelord. For three seasons, Aang has been training to become more powerful than Firelord Ozai. One of the best series finales of all time (certainly in kids' media) wasn't afraid to flip your expectations. Sure, the series finale has a slight advantage in this ranking since it's the length of four separate episodes, but the primary reason "Sozin's Comet" gets the top spot on this list is because of how perfectly it resolves all the plotlines and character arcs that built up over three seasons.
