Name: Zen Kai "Rogue"
Age: (14+) 18
Nation: Fire Nation
Powers/Skills: Swordsmaster: The new Four-Bending Sword Style. Using his skills of the four nations, Zen has invented a type of swordmastery that involves the four elements, to an extent. Not their abilities, but the technique. Here's how it works.
The fighting style of Waterbending is mostly flowing and graceful, acting in concert with the environment. Waterbenders deal with the flow of energy; they let their defense become their offense, turning their opponents' own forces against them. In this way, Zen uses his sword skills as well, flowing and pulling movements. Firebending is notable for its intensive attacking style and general lack of adequate defense moves, which is how Zen uses this sword skill, an all out attacking motion. The key to Earthbending is neutral jing, which involves waiting and listening for the right moment to strike and when that moment comes, acting decisively. In other words, Earthbenders generally endure their enemies' attacks until the right opportunity to counterattack reveals itself, then strike with unyielding force. The key to Airbending is flexibility, finding and following the path of least resistance. Airbending is notable for being almost entirely defensive, and Zen uses it as such.
Together, Zen can use each different bending style as a type of stance and different sword style; The offensive and intense Fire Sword Style, the Elegant and defensively offensive Water Sword Style, the enduring and patient Earthbending Style, and the flexibly and defensive Air Sword Style.
Appearance:

Personality: Zen Kai is an enthusiast. He is always asking questions, and butting in when he isn't supposed to. When people say it's none of his business, he MAKES it his business. That's just the way he is, nosy, but always searching for answers. As smart as they come, Zen is quick to think on his feet, and quick to make decisions. He is kind, and believes in the sanctity of life, never killing anyone, if he could avoid it. He would often speak his mind, and tell the truth, even if it leads him to tough and tight situations. That's just the way he is. he disbelieves in deceit, preferring the straightforward approach in speaking. He has open views about everyone, and loves other cultures.
Zen is friendly, and gets along with almost anyone, but also dislikes and hates people who are merciless. Zen hates war, seeing thousands fight and die is beyond unpleasant for him.
History: Zen Kai was born in the Fire Nation. From a young age, he was interested in the histories of the other nations and the different cultures they represent. When he was 5, upon requesting his parents, he was sent to study with the Southern Air Nomads. There he stayed for 3 years, both making many friends and gaining quite a bit of opinions about the world through their eyes. Although he didn't know air bending, he used air bending principles and applied them to his daily regiment of exercise, which he would in later life apply to his study of the sword.
After spending another two years at home in the Fire Nation, Zen, at age 10, asked to be sent overseas to study again. His progressive parents, more than happy to see his soninterested in the other nations, agreed to send him to Northern Water Tribe.The experience was much different than the one among the Air Nomads, but Zen loved every second of it. The hospitality was wonderful, and Zen began to pick up study of the sword, of which the Water Tribe was fairly good at.
After spending 2 years with the Northern Water Tribe, Zen came home once more. He combined what he learned in the two other places he visited, and began forming opinions and strengths about the world, and about himself. He also added to his sword style a Fire Nation approach, to go along with the Water Tribe style, combining a unique, new style. Zen spend 4 years among the Fire Nation once more, studying both in school and learning the ways of the sword.
Zen set out once more to the Earth Kingdom, to learn more about their vast history. He had actually visited multiple cities while there, first spending a year in Omashu, before moving to the capital of Ba Sing Se.It was from there that he saw the first hints of neglect, of war, and of plotting, scheming, and tyranny. The Earth King, Solus, was just assassinated, and the entire nation was in an uproar. Zen observed as the entire nation slowly turned on the others, including his own Fire Nation. Being for him to remain in the open as a citizen of the Fire Nation, he adopted Earth Kingdom clothes and went into hiding in Ba Sing Se. He first wrote a letter to his parents, explaining that he was fine, and that he was planning to try and do something about this.
It was a dark time, and making matters worse was the Water Tribe going into a Civil War, and the Air Nomads being blamed for the entire thing. But Zen had been to all of these places. He knew it was unlike them. There was something else at work here, and Zen was determined to find out what. He wrote over 100 identical letters, and sent them all across the nations. He would be lucky if he even got one response to meet him back in Ba Sin Se. Some he sent to the places he stayed, hoping to get some of his friends he had met over the many years to come with him and help him find out what happened. Others he sent to towns by the dozen, hoping there might be a single soul who share his ideals about stopping war, and figuring out what really is going on.
While he stayed in Ba Sing Se, he decided the citizens from the inside, making his way around, doing whatever he possibly could to prevent war from continuing, including cutting supply lines, ambushing new recruits, and plenty more good stuff.