Up until the finale of the first plot series, adventurers were indeed called to action by a Gold Dragon in a dream. The premise being that all called had a role to play in the defeat of Bloodstone. Our older adeventurers often are refered to as Dragon Called.
With Blood's demise in the plot finale and the death of the Dragon 15 months ago, [Real Life, 20 ish years In Game] adventurers are no longer called by the dream. Their reasons for adventuring are their own as is their purpose.
We hope to release an updated version of the Player Handbook sometime in the future to deal with these new occurances.