Some dragons are mean, snarling beasts who hulk about and pick on anyone and anything smaller than them.

...This is not one of those dragons.

This guy was content with a life of peace (Notice he's got a peace medallion around his thick neck!). He shared his wisdom with the village, and they shared their food with him in return. Turns out dragons evolved to go long periods of time between meals, so when given a steady supply of justly earned rations, it had quite the effect on his figure.

Yes, he grew quite large, but it's a nice, tranquil life.