Daranon first came to the city-state of Morgan as a travelling mercenary seeking employment (having been exiled from his homeland for refusing to an obey an order from his liege that he thought was dishonorable). He was quickly challenged by the ruler of Morgan's current sworder, and trounced him handily. Impressed by Daranon's prowess, the ruler quickly offered him the job of the man he had dispatched.
The area around Morgan was plagued with a number of monster populations, which had been causing trouble in the area for some time but until now no one in Morgan had mounted an effective counter-offensive. Daranon put together a plan to rout out all the hobgoblins and other humanoids, and defeated them soundly with minimal losses. This won him great approval from the people of Morgan but not from their ruler.
The ruler of Morgan had been ransom to a figure known only as "Gloust", and apparently these humanoids were somehow under Gloust's "protection" (ie, they were victims of the same racket). Morgan's ruler was worried that now Gloust would take revenge against Morgan for what Daranon had done - and soon, minions of Gloust came and raided Morgan's treasury.
When Daranon learned the full story, the solution to him was obvious - track down this Gloust, take a big enough force of men, and kill him. He would not be dissuaded with this path, either. It wasn't until after his army had fought a pitched battle against Gloust's humanoids and Gloust had finally taken the field that Daranon found out just who Gloust was... a dragon.
Daranon insisted on fighting Gloust in single combat. He would not allow any of his men to follow him to the field where they met. Daranon won, though only barely... his opponent's (a fang dragon) bites left bitter, magical wounds that no healing, mundane or magical, could undo.
To wrap up this story, with Gloust's sizable hoard, his already almost total control of Morgan's military, and his fame and approval as a now legendary dragonslayer, it was short work for him to take control of Morgan. He had armor and a shield fashioned from the scales of his vanquished foe, and somehow aquired about that time a life-stealing sword.
Now Daranon is recovering from his battles, and starting plans to take over the neighboring city-states. He has a vision - him, as ruler of the entire world - and he knows he has the determination, genius and sheer will to achieve it, in time.