Sozin

Firelord Sozin was a prominent villain in the cartoon series Avatar: The Last Airbender.

Origin
In his youth, Firelord Sozin was a normal young man living in the Fire Nation, and he was the best friend of the future Avatar Roku. When Sozin became Firelord, his lust for power finally revealed itself. He attempted to conquer all other nations and bring them under the Fire Nation's rule. His friendship with Roku ended when Roku attempted to stop his invasion of other nations. Roku spared Sozin's life in honor of their former friendship, however, this action would claim his life. When a volcanic eruption threatened to consume a segment of the Fire Nation, the two joined together to stop it. Then, Sozin allowed Roku to die in the destruction, realizing that no one would be able to stand in his way if Roku disappeared.

Goals and Ambitions
Sozin wanted to conquer all nations and bring the Fire Nation to ultimate supremacy. As the first act of war, he used a powerful comet to strike down the Air Nation, realizing that the next Avatar would be born there. This comet was later dubbed "Sozin's Comet". Later on, he attempted to wage war with the Earth and Water Nations.