With Toph joining the team, Aang finally had all his bending teachers. Next, they needed to teach him bending as they traveled toward Omashu.
The first thing Toph did after joining was accept Kahn's earlier invitation to an all-out fight, and then-
Unsurprisingly, she lost.
"One flies through the sky, and the other leaves no trace when he steps. That's just cheating!"
Toph shouted indignantly.
When it came to head-on combat, Toph's talent was top-notch as well. Her masterful earthbending and exquisitely precise senses complemented each other, making her practically unbeatable on solid ground. At first, she and Kahn were evenly matched.
During this battle, however, Kahn made two new discoveries.
The first was that Toph had a fatal weakness: being blind, she could not detect things in the air.
Unfortunately for her, Kahn could fly for short periods using firebending. Once he was airborne, Toph was left groping blindly in the truest sense.
That was why the match ended in Toph's defeat.
Even more unfortunately, Aang countered Toph even more clearly. As an Air Nomad, his every movement was light, and once he used airbending, even his footsteps became difficult to detect. He was practically her natural nemesis, handing her a second defeat.
Kahn could not help marveling. Flying types countered Ground types-Pokémon had not lied to him.
The second discovery concerned a weakness inherent to earthbending, or rather, the upper limit of the earth element.
From what he had seen so far, earthbending could manipulate soil, sand, and rock, making it extremely powerful and practical. Yet even the hardest rock struggled to withstand the tremendous destructive power of combustionbending and lightningbending.
In other words, in terms of the upper limit of destructive power, earthbending struggled to rival firebending.
Of course, that being said, lightningbending was an advanced form