Kozhun
Known as the "Evil Dragon" or the "Dragon Tyrant", this green dragon swept out of the lands south of Ikela with an army of zandolit, humans, and other dragons, along with some dragon riders, in about 250 BC. He conquered what is now Ikela and subjugated its peoples under his claws.
His capital was in the middle of the great "island" of Jaoshepar, building a city that was abandoned after his fall (and considered cursed).
Policies
Kozhun's policies are best described as "stationary bandit". He extorted taxes and slaves from the conquered peoples, subjecting them (via viceroys) to his every whim. Rebellion, refusal to pay taxes, or even just displeasing him (or failing to amuse him) resulted in raids by his draconic allies.
Downfall
In 97 AC, heroes gathered in Mirzapur and a rebel army (aided by the Moonshell Dragon Flight and the undersea residents of Ikel'Mer) drew the Kozhun's attention (and that of his forces) away from the heroes. They entered his lair, destroyed the source of his power (said to have been stolen souls trapped in glass vessels), causing him to falter and be downed by the ancient of the Moonshell. He was then killed by the common folk of the rebel army and his army was scattered.
Of course, not everyone agrees with this tale...