Twitter #dnd Idea from November 26, 2012
An evil wizard has located one of the lost Orbs of Dragonkind and sent agents to retrieve it. The Orb of Red Dragonkind gives the power to summon and enslave red dragons. As an artifact, it cannot be destroyed by normal, mortal means. In this case, it must be consumed by a red dragon in a special ritual dedicated to Tiamat to destroy it.
The PCs learn of the discovery and know they must retrieve the Orb. Ideally, because it is such a powerful weapon, they should destroy it. But they do not know how. However, they are approached by a blackguard of Tiamat (or else, they seek her out).
Tiamat wants the Orb destroyed because it is an affront to her children that they might be enslaved. But she cannot trust anyone but one of her agents to claim the Orb for fear they will use it rather than destroy it. She cannot even trust other dragons to retrieve it because her children are so selfish they might use the Orb rather than destroy it. Even a red dragon might simply turn the Orb on other reds to rule over all red dragonkind.
The blackguard worships dragons as the perfect creatures and believes they are the rightful rulers of the world. She is a fanatical dragon worshiper. Tiamat has directed her to retrieve the Orb and has promised to turn her into a dragon if she does so. The intention is to turn her into a red dragon so she can destroy the Orb. The blackguard would never allow an artifact to survive that allowed any human power over a dragon.
The PCs must decide what to do and whether to ally with the blackguard. She does not try to hide her motives or deceive them. In her, Tiamat will have a faithful sacred red dragon. They might seek to double-cross the blackguard and kill her once the ceremony is complete. They might choose to retrieve the orb and seek an alternate means of destroying it, earning them powerful enemies in the evil wizard AND among evil dragonkind, the blackguard, and Tiamat. Bahamut’s faithful might seek to retrieve the Orb and use it against evil dragons. Other gods might turn against the party seeking to destroy the Orb now that it has been found.