Fire and rock filled the sky, Earth and water dropping into the planet. The world was ending, the only thing still alive is the planet's dominate species. Dragons!
The largest and most powerful, Magmathor, sat on a stone outcropping holding a sack made of the hardest substance known. Magmathor had torn off his own jaw to make the sack. As he sat there, millions of dragons were killing each other. Each one carrying eggs. Those who got close enough would try to get their eggs into the sack. As a nasty group of brood mothers flew in, Magmathor disappeared into the sky. Only the fastest breeds could keep up. A couple of them got their eggs into the sack before Magmathor dove into the planet's core. The planet exploded sending Magmathor into space with his eyes wide. He spotted a new world and turned so his back was facing it. Almost as if it had been waiting for him, the star went supernova. Magmathor opened his winds and cought the force of the explosion and rode it.
After an eon, Magmathor's corpse landed on the planet he chose.
We are the first wave of hatchlings, and this planet is massive. The bugs and birds are our greatest threat while we are this size. Who knows how big things get on this world. If dragons have any say, tiny things can grow to be larger then anything else in the world.
So after we start and get going we can plan when to do time skips as we go.
Who wants to be a Dragon!