Though Avatar: The Last Airbender started out as a children's cartoon, even casual fans would be quick to point out how mature it was. The main attraction to the world of Avatar is the art of bending, the ability to manipulate the elements through martial arts. But when this power is applied in deadly ways there are lethal results.
Lightning bending, combustion bending and the Avatar State itself may get all the credit for raw power. However, when it comes to specific techniques or one-hit kills there are no better moves in Avatar than these techniques below.
LIVE BURIAL
Live burial comes as one of the most straightforward moves on the list but surprisingly sees very little usage in the shows or comics. Earthbender's mastery of the ground allows them to suck their opponent's right into it, burying them alive. Bumi partially used the move against Aang in their first duel, turning the ground beneath his feet to quicksand, and General Fong threatens Katara with it to send Aang into the Avatar State. It's rarely used in fights, but with how deadly it is it's hard to see why not.
BLOODBENDING TORTURE
Bloodbending, in particular, is often regarded as one of the most over-powered moves in Avatar. While Katara and Hama seemed to master the sanguine art in Avatar: The Last Airbender, it was Yakone who showed what it was truly capable of in The Legend of Korra. Beyond just using bloodbending to incapacitate his foe, Yakone actively tortured Aang with it by twisting his limbs around and inducing severe pain. Aang needed the Avatar State to even escape the torture, and there's no telling what Yakone may have done to the Avatar's body if he hadn't escaped.
BREATHBENDING
Legend of Korra also introduced a bending technique that fans never thought they'd get in a kid's cartoon. Because most airbenders are pacifistic monks, the idea of bending air directly out of someone's lungs went unconsidered for years. But when the violent revolutionary Zaheer develops airbending, all bets are off as he uses the art to suffocate the Earth Queen in one of the series' most chilling moments. He attempts to use the same technique on Korra later, but Avatars have a way of wriggling out of such dire situations.
What does limit the move is that it seems to take quite a bit of time to perform. The only time it works successfully was against the Earth Queen, a surprised and frail old woman with virtually no combat abilities. The only other time, on Korra, she was able to survive it despite suffering from poisoning at the time and severely weakened. The move may be gruesome, but it's not quite the worst on the list.
EARTH SPIKES
Far more than any show or comic before it, the novel The Rise of Kyoshi gave an opportunity to explore the world of Avatar in a far more adult manner. Part and parcel with those adult themes came explicit violence, unhampered by network censorship. The novel's villain, Jianzhu, was able to wield his earthbending with violent precision.
Throughout the novel, Jianzhu repeatedly shows off his ability to launch projectiles of earth so quickly that they tear through the bodies he targets. In perhaps his coolest scene in the novel, Jianzhu eviscerates an entire canyon filled with archers by summoning spikes from the earth throughout the canyon, turning those attempting to assassinate him into pincushions. It's possibly the deadliest move on the list, but fans will need to way for the sequel The Shadow of Kyoshi to see if the Avatar herself would ever learn it.