This Mynci came across the Wand of Wishing and wished to be the ruler of the world. The wand granted his wish - creating the world of Petaria for him. After a time, he grew bored of ruling and disappeared. When Fluffy came to Petaria, the Founder was pretending to be a thief in Miamecca city. He guided the hero to the Wand of Wishing, and later helped him reclaim it from the Werhond.
While disguised in Miamecca, the Founder looked more like this: