Pet Dragon
Dragons are common in the world, especially in Drrajh, but most large dragons in the wild, were born and lived as pets for their first hundred years or so of life. Often freed once reaching 10-20 feet long.
It is a great honor for a mother dragon to gift her egg to a family. Once she does, that family raises the baby dragon through the generations until it is ready to live in a Dragon Sanctuary.
Raising a baby dragon is a challenging task for a family, and only 1 in 33 dragons live past 50 years, and fewer making it to 100 years old. However once a dragon reaches 100 years, it's chances of death become almost nil, and the dragon can live a thousand years. But the first hundred years are such a challenge that dragon entrust the humanoids to raise them, because the chances of survival are better being raised as a pet than in the wild.