Expanding on my Awakening a bit, and explaining how despite being a decent Earthbender Xin still fits into the first tier.
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In the aftermath of the Disaster of Omashu, Xin found himself just a single soldier in the shattered Earth Kingdom army, scrambling for a retreat from the Fire Nation army - and their Dragon General. Somehow, the Fire Nation had managed to train themselves a fighter who broke all the normal rules of Bending, and had given him command of their army.
He could somehow
fly, great jets of flame holding him in the sky. His golden armour was of a design no-one had ever seen before, and seemed to actively shrug off hits that would have killed anyone else on the battlefield. Even the Terra Team detachment, landing a strike with what seemed to be half of the hill they were stood on, had only managed to delay the figure for seconds.
And the Lightning Breath? That was just
not fair. Even the most elite Firebenders could only use a handful of them attacks, and they took physical effort to use. The Dragon General just breathed out a constant stream of the stuff, and if Xin hadn't been seeing double at that point, he would have sworn it jumped between people too...
Oh, and the worst part about it? His Bending had stopped working. Well, not completely, but now it took a
ridiculous amount of concentration to do the most minor of bending - it was like being back in school. He'd eventually managed to figure out how to use the basics again, though it seemed to use a lot more focus and a lot less gestures than before. It did make him quite happy for his Father's paranoia all those years ago.
"You never know when you might not be able to earthbend! So you will be learning to use a sword!"
That had been an argument over several days. Eventually he had backed down on his youthful arrogance and agreed to learn. It had taken a decent chunk of his free time, and even now he was hardly a master, but he knew his way around a sword better than most of the farmers that had joined the army. It had probably saved his life or health at least twice since the Disaster...
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So, he had been a decently-talented earthbender, but his 'Awakening' shifted his abilities in such a way he lost a lot of the power he had before.
Though in writing this, a question has come up for
@RogerD. Are there other Travellers of the Grand Stair than us? Or would 'The Dragon General' simply be an Awakened person locked to that world?